Reddit mentions: The best bike derailleurs

I'd make this comment even longer if I could, but I'm tired. I've got a 1975 Raleigh Grand Prix and have done everything and more to it, and can answer any question you have when you start working on it. I also race a 1974 Raleigh International in collegiate races and some of the parts are from a Grand Prix. Most of your stated questions were already answered so I'll address some other things.

Check the serial number on the bottom bracket (or left rear dropout). 1974-onward models are on the bottom bracket and have a logical serial number that works as follows: My serial number was WB5... which meant W = Worksop factory, B = 2nd fornight (2-week period) of 5 = 1975. The Worksop factory was the best and the N = Nottingham factory was the worst - not because of build quality, but because they used non-standard bb and headset threading (26tpi). My Grand Prix had a 24tpi standard bb and a Raleigh 26tpi fork/headset, so I'm not sure what happened there.

The drivetrain should be just fine with a replacement chain - my recommendation for any 5-8 speed application is a SRAM PC830/580/870. Sunlite sells a very affordable but effective rear derailleur if you want to replace yours, but the existing one should work fine. The front derailleur will also work great, and I still use that same model. Those downtube shifters, IMO, are actually better than same-era Campagnolo shifters because honestly, levers are quite simple, and these are very solid and have a nice, sharp edge that makes flicking them with your fingertips very easy. I recommend removing the washers and cleaning them, or cutting new ones out of a thin sheet of copper - made mine just like new. For what it's worth, the Huret groupset was a nice step up from the Simplex groupset, and the all-metal Huret components will work just great, particularly with that new chain. Regarding the cottered crank/bottom bracket, be sure to either re-use the original hardened steel cotters or new ones from bikesmithdesign.com. Do not remove or reinsert them with any tool other than a cotter press. If you follow the right directions, servicing them is actually quite simple. Repack and set the bearings carefully, and you shouldn't have problems - Raleigh cups and spindles are legendarily hard and wear-resistant. If you need a new freewheel, be sure to get one with a 14-17-20-24-28 combo (or a 6-speed Shimano 14-28 freewheel), NOT one with a 16t 4th gear in place of the 17, because it's mathematically incorrect. That one is matched to a 52/40 crankset - if you get something with a 14-16-19-21-24-(28), technically a 52/42 is the correct matching crankset. I wouldn't do a 7-speed, spreading the frame and figuring out how to space it properly will be a headache.

Regarding the paint - you may want to keep it as-is and just sand and touch up the rusty areas. This is a high-tensile steel bike (though a nicer one), so I am almost certain not enough metal got rusted away to damage the thicker steel tubing. The paint, however, was generally very good, and is a candy-coated finish that looks very good touched-up. You won't be able to replicate it. I would keep it.

For potential improvements, your best bet is the wheels. While I wish I had kept my Maillard hubs, the steel rims are unfortunate on these frames. Alloy rims are an excellent upgrade, as are moving to 700c rims and getting some nice tires (Clement Strada LGGs are decent). It'll shave a lot of weight while leaving the bike's character intact, and gives you a lot more tire options. You may notice the front brakes are Weinmann 610s and the rears are 750s. The rears are longer-reach than the fronts (this was common practice among bike manufacturers, though I have no idea why). In my experience, putting a 750 on the front will be enough to run 700c rims front and rear.

Keep in mind this is a high-tensile frame, albeit a nice one, so don't go too crazy. I ultimately moved up from mine to an International, but the Grand Prix is still in my stable and I ride it whenever I go home (college student). It's got Nervex lugs and imo the geometry is decent. Just take good care of it and you'll have it a long time.

Depending on what you are looking to do to get back running you obviously need a new derailleur, you can pick up a 7 speed Shimano for relatively cheap (only Shimano, SRam/Campagnolo use different pull ratios and therefore wont work with your shifter) the exact one you have is in this link https://www.amazon.com/Shimano-8-Speed-Mountain-Bicycle-Derailleur/dp/B0064QKTW8

Looking at the shape of your derailleur and the amount of torque that thing saw there is a good chance you will need a new derailleur hanger from the looks of it you might be #13 http://derailleurhanger.com/specialized.htm Now, there is a chance the old hanger is fine, you could always throw the new derailleur on the bike first and see if everything is lined up (if the derailleur is not parallel with the gears you need a new hanger).

I would also look at putting in new cable and housing, you can pick that up pretty cheap, just make sure it's for shifting and not brakes.

When you look to hook all this stuff up do yourself a favor, watch a few youtube videos about adjusting your new derailleur, it's not that hard but a proper setup can make a huge difference, and it's best to have it dialed before you start skipping gears on your ride. New chain as you mention is a no brainier, make sure it's a 7 speed chain (other chains are different widths). When you get your new chain clean it with some simple green or other degreeser (while you have that degreeser out give that cassette a good cleaning) once you have it all good and clean rinse, rinse, rinse, don't leave any solvent on the chain or cassette, then use some chain lube (not WD40 or oil), depending on where you live you may want different lube (follow directions, some require quick wiping some don't).

Last piece of advice is take those brakes slow, those pads might be shot.

I think you're rolling a 2000 version of your bike the 2003 version was 8 speed but you can check the specs listed against what's on your bike and narrow it down.
http://www.bikepedia.com/QuickBike/BikeSpecs.aspx?Year=2000&Brand=Specialized&Model=Hardrock&Type=bike

Good luck, get rolling.

While some shifters are better than others, at this price point, they all will be about the same. If you want thumb shifters, that is a perfectly valid choice. There are also some trigger shifters out there, as well as grip shifters if you wanted to keep that style. As long as the shifter is shimano compatible, and 7 speed, it will work with your current freewheel and derailleur.

>As for what you described with the current drivetrain, what i think I'm seeing you suggest is 'clip the front derailleur off/remove it, leave the current crankset on with the chain at the middle gear since even though not optimal it current funds can be better spent elsewhere.' Am I reading that right?

No. The bottom bracket axle length will determine how close to or far from the frame the chankset is. This article on Chainline may be of some help.

What I was suggesting is that you can still change the crankset, and leave the derailleur in place as a chain guide (tighten the limit screws to ensure that the derailleur is centered over the chainring). They make purpose built chain guides, but the derailleur is already there and will work, so free chain guide.

As far as the rear derailleur, you have a claw mount derailleur, so for anything "better" than what you have, you will need an adapter. As far as upgrading the derailleur, I would personally go for something along the lines of the Altus M2000 or Acera M3000. Note that these are "9 speed" derailleurs, but the cable pull is the same as 5-8 and the shifter dictates the "speeds" shifted, so they will drop right in.

Pedals, Rockbros are the current king of the inexpensive. They come in a few colours, so you can match that to your taste.

Weeding the bad out is sometimes as easy as reading reviews, yes. However, look beyond the amazon for reviews. I generally prefer a video review, so I frequent YouTube for them, but google/duckduckgo can usually find a few forum posts as well that will answer questions.
It is also sometimes as easy as knowing a trusted name, and using their part over a shady one. Shimano and Sram parts are usually trusted and reliable on the drivetrain. Rockshox, Fox, and Manitou are good for shocks and forks, but Suntour is also sometimes good. There are more brands that are great, but on the low end price point, just play it by ear.

The bike started life as a 2012 Motobecane Fantom Cross Pro, which came with some good components already. SRAM Rival partial group,
FSA crankset, and Mavic Aksium Race wheels. I've had good luck with this bike and it's got almost 2k miles on it, so I kept most of it, but not all.

Once I decided to make it my commuter bike, I started adding things.

For lights I picked up the Cygolite Hot shot rear light and use one of my MTB lights if needed for the front, a
Chinese knock-off CREE XM-L2 front light

For tires I went with the Panaracer RiBMo 700x32c based on feedback from users on here.

You can't go wrong with a Tubus Logo Evo Rear Rack and Ortlieb Back Roller Classics.


I wanted some extra gearing for those climbs along the way, so I went with the SRAM FORCE Rear Derailleur so I could run a SRAM PG-1050 11-32 Cassette.

Of course, I needed a new KMC X10SL chain for the new gear combo.

I picked up a new road bike and pulled the Ritchey Pro Streem Saddle and Ritchey Pro Biomax bars off of that bike and used them on my commuter, along with some new Lizard Skins DSP 3.2mm bar tape and some Soma Road Flares for added visibility.

For a little less weight and possible shock absorbtion, I threw in a Chinese knock off carbon seat post.

I also wanted something besides my regular riding shoes, so I opted for the Shimano Click'R PD-T700 pedals and
Shimano SH-CT40 Cycling Shoes
, which I love and highly recommend.

I also needed to adjust the fit so I picked up a Kalloy Uno 6 90mm stem because I've had great luck with them on other bikes.

And for added safety, I picked up two rolls of 3M Scotchcal Reflective Striping Tape in white and black, and added white stripes to the white frame and black stripes to the rims and the back of my helmet.

> You need to pinpoint exactly why you're getting flats before trying to throw money at a problem and expect it to be fixed.

I have been getting some flats from "goat heads", but those are the normal slow leakers. The flats I got on the trail Monday were pinch flats. I verified this by looking at the tire and tubes. The tubes had the "snake bites" that tell me it was definitely a pinch flat.

>What tire pressure are you running. Have you checked your rim strips.

I was running 35PSI when I got the first one and was running 25PSI on the second one.

>Have you checked your rim strips. What type of terrain are you riding. How old and what condition are your tires.

I replaced my rim strips when I replaced my tires at the beginning of this season. I replaced them with another set of Specialized Ground Control tires since I'd had no problems with them. So the tires and rim strips were less than six months old.


>For mtb however, the larger cogs were able to be placed practically over the hub flange which means that all freehubs from 9spd and up will work with shimano style cassettes.

This s truly exciting news! I'd much rather do an 11 speed cassette and be able to lose as little gearing as possible. Also I've seen some 11 speed cassettes that go up to 50 tooth, so that might be an option.

>The cheapest 1x setup right now I believe is the M7000 SLX setup for around 200 bucks not including the cranks.

I saw those, but I was thinking about spending more for the XTR derailleur and shifter. I don't know that it will make a huge difference to my shift quality, but I like to go with the best I can afford.

All things said and done, the rear rim will have to be replaced, but I really appreciate your information about the gears, so I don't have to replace the hub (I've never had any issues with it!).

I appreciate your recommendations here. If I can just replace the rims and give the hubs a rebuild at the same time. That would probably be a better investment. It's been a long time since I've built a set of wheels, so I'd probably give them to my LBS to do the work.

I weigh a lot more than you, so I'll look at the Stan's Flow wheels and talk with my bike shop.

Thank you very much for your reply. I know what I posted was barely coherent. Do you have any experience with the Cush Core or similar products?

my bike is a rehabbed 99 GT XCR-4000. here's a brief summary of my current configuration, with costs & reason for replacement. I should note that I wanted to buy a cheap bike to get into the sport and learn how to do maintenance so if I got a nice bike I wouldn't be actively destroying it. I've had the bike for a few years now and replaced a bunch of things. anyways, this is roughly in the order that I replaced things.

Stock: Frame (duh), seat tube, head set / stem.

new:

Shifters: Shimano Alivio 3x9. the shifters were shot when I bought the bike, had a set of microshift ones that lasted a year but sucked and broke. $65 for the pair

Drivetrain: new chainrings $10-$30 each, cassette $35, chain $22, Front Derailleur $20, rear derailleur $68. The drive train was such a mess when I got the bike, I've destroyed some good components from being a noob. all straight now though. kept the 3x9 arrangement since the sifting wasn't holding back my riding at the time.

Fork: Rockshox recon silver solo air $200 the 15 year old rockshox judy was sticky, heavy (coils) and the only damping was the stiction of the tubes. Super happy with the replacement, it's steel so not super light but the adjustable rebound damping made a huge difference. when I bought it they had rim brake mounts as an option on the amazon page, not sure if that's still available. the rim brake version that I have does have disk mounts as well.

Wheels - $100 craigslist. the stock wheels were a mess and impossible to true well - I broke a spoke on my rear wheel which then got sucked into my RD, destroying that and breaking another couple spokes in the process. decided to say screw these old things and bought a new set of wheels, this time with disk brake hubs - thankfully my frame had mounts for the rear.

Disk brakes: avid bb-7 - $60 ebay(new). purchased at the same time as the new wheels, went with mechanical because I didn't want to deal with bleeding hydraulics, though this is the one thing I would change. I would get hydraulic brakes because I feel like I'm adjusting the pads on the mechanicals every ride or two (huge pain in the butt). Also bought avid FR-5 levers $16

handlebars - Ritchey comp alloy $30. crashed and bent my bars pretty good. I didn't want to change out the stem so I bought the closest approximation to the stock bars that I could find cheaply. also decent 25.4mm mount bars are freaking impossible to find.

I should note that this is certainly not the proper way to maximize the quality of the bike for the money. The total is around $700, though I've spent more than that over the 4 years I've had the bike since I've replaced a couple things multiple times (chains, etc.).

if you want a retro bike, these are the best things that I've found to replace the components as they break. If others have found better stuff in terms of bang for your buck, let me know. The only things I've replaced to "upgrade" the bike are the fork & disk brakes, though since it was time for a new wheelset the brakes made a lot of sense to purchase at that time.

Thread rejack! I noticed that the bike in those pictures has the same style lower mounted front derailleur with a brace (not a clamp) as the one I thought was broken on my bike. Cool.

Also, in my novice opinion, that bike looks great. If it's comfortable, I wouldn't hesitate to grab it at $400. A new entry level bike like a Trek 820 will run you about $360 + tax. I think for a few bucks more, this would be a superior bike.

Take for example the rear derailleur. The 2007 comes with a Shimano Deore (confirmed in the pics). Here it is on amazon for $50. A new 2012 Trek 820 comes with a Shimano TX35. This goes for $12 on amazon.

Again, take this with a grain of salt as I just bought my first bike. This is just from some of the knowledge that I've gained in the past few days. Good luck.

*grammar edits

Oh wow after going back to the amazon link it does in fact say dual pull design

anyway here it is http://www.amazon.com/gp/product/B0063R0ZUO/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

Do you know of a good resource to figure out how to flip it around or whatever is involved? It didn't come with instructions just a derailleur in a box haha.


Thanks for your help by the way I do appreciate your time!

Sorry about the late reply, but here you go:
Shimano Acera 6/7 speed rear derailleur:
http://www.amazon.com/gp/product/B000F5EGAA
It has plastic roller gears for the chain! I have not ridden it much, but something tells me when a stick lands in, it won't shred it up like my xtr. You might want to spend more for a better one.
I'm not sure what the cage length is but if you get another, you'd probably be best off with a medium cage, but you might need a long cage. Check this for more info: http://forums.mtbr.com/showthread.php?t=205890


Here is the cassette: http://www.amazon.com/gp/product/B001BY7ZP2
I got the 13-30, but I think i'd recommend the 13-34 for the lower gearing.

I scored this Rockhopper for $50! Now I’m looking to modernize pretty much the whole thing. Please critique my build list below. Would you get anything different, or better, or maybe anything else that would be better value? Did I miss anything? Do you think all of this will work together? It will be my adventure bike for bike packing, gravel, off road touring.

FOMTOR 25.4 stem 60mm 35 Degree Bike Handlebar Stem Riserhttps://www.amazon.com/gp/product/B07G71CZG6

UPANBIKE Road Mountain Bike Bicycle Stem Riser Adapter 1 1/8" φ22.2mm https://www.amazon.com/gp/product/B071LLR8PR

Action 1-1/8" W/Adjuster Black Cable Hanger Fronthttps://www.amazon.com/gp/product/B06XCSKWCQ

KMC X9L 9 Speed Chain Gold Coatedhttps://www.amazon.com/dp/B0789HPV7M

Wheel Set 26 x 1.5, Mavic x M117, Deore M530 9Sp Hub, Blk SS Spokes, 32Hhttps://www.amazon.com/dp/B0033H53VI

Shimano Deore 9-Speed Mountain Bicycle Rear Derailleur - RD-M591https://www.amazon.com/dp/B003OWPRLI

Maxxis DTH 26 X 2.15 60A Kevlar Blackhttps://www.amazon.com/dp/B004XIT4YS

XCSOURCE MTB Mountain Bike Crankset Aluminum Bicycle Crank Sprocket and Bottom Bracket Kit 170mm CS400https://www.amazon.com/dp/B01LWXUV7I

RaceFace 104mm Single Chain Ringhttps://www.amazon.com/dp/B00D3FG6ZW

​

Edit: Adding Shifters and Cassette

SHIMANO Deore SL-M590 9-Speed Shift Lever
https://www.amazon.com/dp/B00IKVJF8Y/

JGbike Sunrace 8 9 10 Speed MTB Cassette 11-40T 1 Wide Ratio Including 22mm Extender - for SRAM Shimano-Type splined freehub Body
https://www.amazon.com/dp/B01MRLWHEO

Will I be happier with the shimano acera?

Its made of steel like my old one and I like the idea of nice shifting on my refurbed bike. Then again I also like money and your recommendation for the matching tourney cheapo model. Let me know what you think.

Pretty sure that's Claris running gear.

The rear derailleur looks like 2300 series.


Here's a 2300 triple crankset in silver ... use your imagination to paint it black and get rid of the granny chainring. Clearly the same family.

This would be typical for a base-level bike built anywhere from ~2010 - ~2015 or so... (leeway one year or the other based upon when the groupset was released and the bike spec'd out by the manufacturer).

no problem. Glad I could help.

here is a bit cheaper one.

The part number on the claris derailleur is FD-2400 if you want to look for it elsewhere since it doesnt seem to be on prime.

They are even cheaper on ebay if you are looking to really pinch pennies.

Gl and feel free to pm if you need help.

That length actually looks perfect. I think it's the rear derailleur just isn't strong enough to hold the chain.

Do you use the big ring, ever?

A possibility would be remove the big ring, and put on a bash guard. Then shorten it so the rear mech looks like that when in the middle ring.

You could also upgrade to a better rear derailleur. Something like this should work fine, and it's not overly expensive.

Sweet. So I am going to go with the 130mm spaced hub you linked above along with this cassette with 34 teeth to help with those mountains, this derailleur with the longer lever to work with the larger cassette, and this 6/7/8 speed chain. Let's hope it all works together!

https://www.amazon.com/Shimano-Tourney-8-Speed-Mountain-Derailleur/dp/B00O7XMG1C

​

Like that one?

​

There are a couple of others that want me to chose between 'direct attachment' and 'with riveted adapter' like this one:

​

​

https://www.amazon.com/Shimano-RD-A070-Road-Rear-Derailleur/dp/B007Q4PBNO/ref=asc_df_B007Q4PBNO

​

Thanks.

​

Watching youtube videos about how to replace and adjust a derailleur right now...

​

(edit: also https://www.amazon.com/Shimano-RD-TY300-Derailleur-Compatible-Upgraded/dp/B01GO02W5K/ )

Thanks, WildMan. I've found the same M310 Altus you've linked to, but it has DL at the end?

https://www.amazon.co.uk/gp/product/B005CMUQU0/

Would this be my best option? I'll order those then.

don't a friggin get an X9 for that bike... its like putting a corvette engine a tercel. doesn't make sense and won't even work. your bike had a tourney rear derailleur which is the most entry level shimano has. upgrade a bit to this acera for $20 and call it a day. It'll shift better than what you're used to and won't break the bank. it will work with your existing stuff as well. simple as removing the busted one and installing this. watch some videos and you can get it done easily.

Upgrading it will be quite expensive. However, it'll provide you with a wealth of knowledge, frustration and, at the same time, fun.

Depending on your existing hub, you may or may not need a new hub to put your new cassette on.

With a wide enough range of gears on your rear cassette you can get away with a single chainring, so there will be no need for a new crankset/front derailleur/front shift lever.

As /u/fclbr said, you can choose downtube shifters in order to keep your existing brake levers. There are also bar-end shifters, and if you go for a single chainring, it won't be that expensive.

All-in-all, consider if this bike's right for you, size and geometry-wise, as your decision may be a bit rash. If it is, then I'd say go for it.

Rear derailleur - $20

Cassette - $20 - I recommend going for the 34t max sprocket. It'll allow you to stick with a single chainring

Bar-end shifters - $55 - they are 9-sp indexed, but they also work in friction mode, which allows you to freely adjust your gear

Downtube shifters - $14

Cables/outer cables are negligible costs.

ok last thing http://www.amazon.com/dp/B007Q4PBNO/ or http://www.amazon.com//dp/B007Q4PGPM/

whats the dif with Smart Direct Mount or Smart Mount with Bracket

Thank you for your thoughtful response.

Someone suggested this, which can take 34T cogs:
https://www.amazon.co.jp/SHIMANO-%E3%82%B7%E3%83%9E%E3%83%8E-%E3%83%AA%E3%82%A2%E3%83%87%E3%82%A3%E3%83%AC%E3%83%BC%E3%83%A9%E3%83%BC-RD-R3000-GS-ERDR3000GS/dp/B01D8CP9B6/ref=sr_1_1?s=sports&ie=UTF8&qid=1506107852&sr=1-1&keywords=RD-R3000-GS

Will the cage itself still crash, though？

Your shop doesn't ship to Japan, does it? xD

if you search for the product number on google you'll find http://bike.shimano.com/content/sac-bike/en/home/components11/road/sora11/rd-r3000-ss.html which says that it is only good for 32 teeth.

this one is good for 34T - see http://bike.shimano.com/content/sac-bike/en/home/components11/road/sora11/rd-r3000-gs.html

edit: do you have friction shifters? if not then you need to also check that the new derailleur is compatible - it needs to move the same amount per "click" as the old one.

this should be what you need, good luck! http://www.amazon.com/Shimano-RD-2300-R-derailleur-Smart-cage/dp/B002UZORHU/ref=sr_1_4?ie=UTF8&qid=1375227246&sr=8-4&keywords=8+speed+sora+rear+derailleur

Lets see, I take it you didn't even look at the 2 bikes.

Trek 7.2 FX.

• Shimano 8-speed shifting
  
  It is all of $25 on amazon. Toss in another $27 for the rear derailleur.
  
  Compared to the 549 EUR http://www.bikemarket24.de/diamant-achat-herren-saphirschwarz-bern-silber.html
  
  
• Nexus 7 speed coaster brake. $329 on Amazon
  
  The price difference in gearing alone is where the difference is.
  
  Also includes a bike rack. A lighting system. Seatpost suspension.
  
  Oh, and a 3N20 Dynamo $90 on amazon.
  
  If you bought the Trek and tried to turn the Trek into a commuter bike like the Diamond you'd end up spending more.
  
  Compare apples to apples and then you can do a price comparison.
  
  Here's a 399 EUR one. 7 speed, with dyno. http://www.bikemarket24.de/hercules-13-city-7-nexus-rt-14518.html
  
  Here's another for 299. http://www.bikemarket24.de/kreidler-raise-rt-limited-spectro-7-gang-13811.html?price=3%2C100
  
  Please link to a commuter bike in the US that even close to that feature set for $392.80 AFTER taxes.

It's a great bike for the price. For what it's worth, I've done plenty of loaded touring in mountains with similar gear ratios (compact crank with 11-28t cassette). Others will say your lowest gear ratio (1.2) isn't low enough for mountainous touring. Depends on your strength and how much you're carrying.

To get it lower, you can buy an 11-34t cassette which will bring you down to a 1.0 ratio.

However, I'm not sure the derailleur it comes with will fit an 11-34t cassette. If it doesn't, you'll need a mountain bike rear derailleur like this.

In short, you're looking at $30 or $70 to upgrade to a traditional low touring gear ratio, not including labor.

That is an 8 speed derailleur, so replacement is very easy! Any Shimano 8/9 speed derailleur will work, new or used. RD-M310, RD-M360, and RD-2400 are three inexpensive ones I found on amazon. Also, going used will often let you get a higher end model for less money. I would suggest either getting a RD from your LBS or if buying off the internet, run whatever you find by us

So, bit of an update, this is what I ordered earlier and wanting to make sure they're compatible/good choices:

Cassette:
SRAM PG850 8 Speed

Rear Derailleur
Shimano Alvio 8 Speed

Chain
SRAM 850

and I was unable to find any 'cheap' single bar end shifters, most were the 'extreme' kind that have bars extended out in front of the rider(unsure what that is called); however, was able to find a 'good' deal for a right Shimano Sora ST3000 8 Speed shifters.

From my understanding, I could mix/match many of the parts except the RD and the sifter should be the same brand. They all should be 8 speed?
The one part that I have reservations about is the rear deraileur as I would prefer something more 'roady' than the Alivio but unable to find any that are '8 speed'; would it be possible to get a 9 speed Shimano RD and have it still function well?

Get this Altus rear derailleur (assuming I correctly counted you have an 8 speed cassette). $21 shipped. Big pulley and jockey wheels are great, it’s a small upgrade from your current model.

Here’s a rear derailleur removal and install video:
https://youtu.be/IN4-jFRD8-Q

Parktool has great videos on adjusting or overhauling a rear derailleur but not one specific to removal and installation.

You can't fix that. Send the pic to the seller and demand satisfaction. Probably the bike was not packed properly for shipping, or the shipper brutalized it.

If you can't get it replaced for free, the part is $20: https://www.amazon.com/Shimano-Tourney-Derailleur-RD-TY300-Direct/dp/B01D2WQ0TM and you can install it easily yourself.

You may or may not need to take the bike to a shop to have the derailleur hanger (silver piece) straightened. If you bought the bike mail-order, ask them to send you a new one of those too.

That's a long cage, which you probably won't need looking at your bike.

See this link for more information on cage length.

http://www.amazon.com/dp/B007Q4PBNO/ might be better. Read the above link though and work out what cage length you need.

Is the shifting indexed (single click for each gear) or friction? If it is friction, get whichever suntour or shimano derailleur is cheapest online. It should be one without the hook also called a derailleur claw. A used one would be less than $20 online, or you could get something new like http://www.amazon.com/gp/product//B000F5EGAA/ref=twister_dp_update?ie=UTF8&psc=1

This is the one I picked up, not sure if it has the clutch on it though. It does seem to shift better than the stock derailleur.

http://www.amazon.com/gp/product/B000YBCNAA/ref=oh_details_o09_s00_i00?ie=UTF8&psc=1

This looks like it might work

https://www.amazon.com/Sunlite-Short-Cage-7spd-Derailleur/dp/B001HD8Q4Q/ref=sr_1_6?s=outdoor-recreation&ie=UTF8&qid=1497773398&sr=1-6&keywords=bike+derailleur

This is tempting then. If all I need to do is drop this in and tension it, I'm probably going to do that vs anything else. Seems like it'll be quite a worthwhile upgrade especially if I can use my existing shifter, chain and cassette !

Misunderstood, I thought you wanted to replace the DT shifters with brifters.

Your bike here is a 5-speed -- which refers exclusively to the number of cogs on your cassette. It doesn't matter how many chain rings you have in the front. 5x2 means you have a 10-gear range, but we still refer to these bikes as "5-speeds".

The problem is this: 5-speed bikes have a spacing for the rear wheel of 120mm -- which is very narrow compared to modern road bikes. You have two options: track down an old 5-speed rear wheel that works, or you could buy a (comparatively easy-to-find) 6-speed rear wheel and bend the frame to suit its 126mm width. While that sounds like a recipe for disaster, steel is supple and wouldn't really mind the 6mm bend. If you go down the 6-speed route, you will need to replace the shifters and rear derailleur to match a 6-speed drivetrain. Do not attempt to buy a wheel that works with 8, 9, 10, or 11-speed drivetrains, as they simply will not fit the bike.

The cassette you linked would work fine for a 5-speed setup. This is an example of a derailleur that would conceivably fit that bike.

For brakes, almost anything will work. Tektro make some very nice dual-pivot brakes that you can make work with that frame.

Bottom bracket is the set of bearings and spindle that hold the crank arms to the frame.

https://www.amazon.com/Top-bike-Tourney-Derailleur-RD-TY300-Direct/dp/B01D2WQ0TM/ref=mp_s_a_1_1_sspa?keywords=tourney+7+speed+derailleur&qid=1572404682&sprefix=tourney+7+speed&sr=8-1-spons&psc=1&smid=A19ZVD46PHVPF7&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExRzRJSFFYOVc2MzZDJmVuY3J5cHRlZElkPUEwNTA4NDI0Mzk3Nlk2NVZJMFRFUyZlbmNyeXB0ZWRBZElkPUEwNDkzNzAwMkYzMUtJMk5OUTVONyZ3aWRnZXROYW1lPXNwX3Bob25lX3NlYXJjaF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

LHT Frame - $520 after tax

Chukker Wheels - $85 x 2

Tires Schwalbe Marathon Plus RLX 700 x 45 C Bicycle Tire - $54 x 2

Alloy Headset Spacers - $7.89 x 2

Shift Levers - $60

Chain - $10

Brake Cables - $10

Brakes - $15 x 2

Extra Long Shift Cables - $6

Derailleur - $24

Cassette - $17

Crankset - $40

Spindle - $24

Headset - $45

Seatpost - $20

Brooks Saddle - $145

Rack - $35

Brooks Panniers - $150 x 2

Brooks Bar Tape - $65

Tools

Saw Guide - $41.36

Starnut Setter - $22

You just need a new derailleur. Basically anything will work, but you can get this guy for $20, you after you swap it over (sort of complicated, but doable with little knowledge), you'll be rolling.