wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim

Apr 24, 19 5:28

Post #1 of 30 (2625 views)

(edit: added drive-side picture as that is more relevant)
(edit2: added tire size, and that I'm based in Europe)

(While it's my commuter bike - though I did my first ever triathlon on it! - I need help with, hope it's not too off topic - as this is the only "bike" forum I hang out on, and many people here are quite versed in bike wrenching solutions my LBS doesn't know (e.g.: rear derailleur extenders instead of replacing the whole RD), so I hope it's OK to ask. Anyway....)

The rear wheel has a Shimano 8 speed internal hub with holes for 28 spokes. I destroyed the old rim, and the two LBS I asked can't source (*) a double walled rim for it (20" diameter, 47x406 tire, dahon bullhead ~2011 folding bike). I am based in Europe (Hungary). The frame has horizontal track/singlespeed style "dropouts", and as far as I can tell it doesn't have a place for a derailleur hanger (see pic). It used to be the kindergarten commute bike, i.e.: child seat + child = "lot" of weight on the back. The rear frame has space for 130mm, so at least that is standard.

Can I get this bike to ride again? I would be OK converting it to an N speed cassette/freewheel on the back, but is there an RD hanger adapter for such frames? Or are single wall rims OK for such small wheels with significant load? I would rather not turn this into a singlespeed bike...

drive side:

non-drive side:

(*) so far we have tried general bike distributors, country brand distributor, BMX store, and a recumbent bike store

Last edited by: bableves: Apr 24, 19 13:17

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 5:37

Post #2 of 30 (2601 views)

You can buy a device that goes on the quick-release or axle that has a threaded hole for the derailleur. You need to manage the shifting cable somehow without stops so perhaps running at continuously right up to the shifter and using zip ties or purchase self-adhesive attachments that are used for hydraulic lines on mountain bikes and then zip tie the housing on to those. You could then purchase a regular 7 speed dahon rear wheel and some junky derailleur and shifter for not much money.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [jroden] [ In reply to ]

Apr 24, 19 5:39

Post #3 of 30 (2594 views)

https://bicycles.stackexchange.com/...ailleur-on-this-bike

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [jroden] [ In reply to ]

Apr 24, 19 5:44

Post #4 of 30 (2579 views)

Sadly, the link is about a forward facing dropout, while mine is rear facing. But now I know bicycles.stackexchange.com exists, thanks!

(edit): hmm, but maybe if I just take the hanger and flip it, and drive the screw from the wheel side into the RD, it should work just as well... or search for a similar hanger, but one which accepts not 10mm, but only 8 or 9 and then have someone 'cut' a new 10mm thread into it..

Last edited by: bableves: Apr 24, 19 6:12

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 5:47

Post #5 of 30 (2567 views)

I once saw a fixie converted to a geared bike with an old school axle-mount derailleur.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [jroden] [ In reply to ]

Apr 24, 19 5:48

Post #6 of 30 (2557 views)

this solution requires re-adjusting the RD any time the wheel is taken out, right?

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 5:52

Post #7 of 30 (2546 views)

bableves wrote:

this solution requires re-adjusting the RD any time the wheel is taken out, right?

Probably, I didn't say it was a good solution. In the old days that bolt head would thread into the dropout to hold it in place when the wheel was removed. It doesn't look like your drop-out has the space to drill and tap a hole there.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 5:58

Post #8 of 30 (2533 views)

Couple questions:
* What's the bead seat diameter on the rim?
* What locknut spacing is the frame made to accept?

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Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [Thom] [ In reply to ]

Apr 24, 19 6:19

Post #9 of 30 (2495 views)

Thom, the style of RD (hanger) you posted is solid once installed, doesn't require any re-adjustments, as the screw holds it firmly in pace. I was trying to reply to jroden's comment about the axle-through hanger, which as I understood that to be fixed by the axle itself

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 6:25

Post #10 of 30 (2481 views)

What happened to the rim?

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 6:45

Post #11 of 30 (2444 views)

bableves wrote:

Thom, the style of RD (hanger) you posted is solid once installed, doesn't require any re-adjustments, as the screw holds it firmly in pace.

True but I don't think you have a place to thread that screw into.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [Thom] [ In reply to ]

Apr 24, 19 7:18

Post #12 of 30 (2395 views)

Any bike shop can get you a rim, that is not a rare thing.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 7:23

Post #13 of 30 (2385 views)

Just take it to your local bike shop and say "I was just riding along when..." and let them deal with it.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 7:29

Post #14 of 30 (2378 views)

Buy a new rim. Simple.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [lyrrad] [ In reply to ]

Apr 24, 19 8:05

Post #15 of 30 (2350 views)

lyrrad wrote:

Any bike shop can get you a rim, that is not a rare thing.

I'm with this answer. A 20" double walled 28 hole rim is a really common BMX rim. You might have to get new spokes because it's doubtful the ERD would be an exact match, but that's not adding too much more to the cost.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [dangle] [ In reply to ]

Apr 24, 19 8:37

Post #16 of 30 (2308 views)

another vote for 28 hole BMX rim. While 36 is more standard, 28's can be found. I have found many bike shops less than helpful with any request outside their direct line of experience. I saw this as a former bike shop employee...

Links below to a couple rims I found:
https://answerbmx.com/...ims/expert-rims-28h/
https://www.ebay.com/...3.l4275.c10#viTabs_0

Next thing you want to do is take that rim to a wheel builder that has a spoke cutting/threading machine. They can build it up with straight gauge spokes cut and threaded to length since this wheel will need some weird spoke lengths based on the hub flanges mixed with a 20" rim. That is typically easier and cheaper than having the shop order in 2 boxes of odd ball sized spokes.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [CyclingClyde] [ In reply to ]

Apr 24, 19 8:39

Post #17 of 30 (2301 views)

Agreed on the spoke cutter. I wasn't sure if that rabbit hole was worth mentioning quite yet if sourcing a rim was already difficult.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [dangle] [ In reply to ]

Apr 24, 19 8:45

Post #18 of 30 (2287 views)

dangle wrote:

lyrrad wrote:

Any bike shop can get you a rim, that is not a rare thing.

I'm with this answer. A 20" double walled 28 hole rim is a really common BMX rim. You might have to get new spokes because it's doubtful the ERD would be an exact match, but that's not adding too much more to the cost.

Which is why I asked about the BSD of the rim. I found 2 each double wall rims in 28-hole for the 451 and 406 sizes (both are considered 20"). And that's just through JBI. I'm sure the Euro suppliers would have similar selections.

---------------------------------------------------------------------
Some are born to move the world to live their fantasies...

https://triomultisport.com/
http://www.mjolnircycles.com/

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 9:02

Post #19 of 30 (2265 views)

What country are you in, and what is the ISO size of your tire? There's more than one 20" standard.

Options:
Sun-Ringle CR-18

Velocity A23

Promax RMV

Sun-Ringle ICI-1

Sun-Ringle Duroc

Buy the rim, buy the spokes, take the old wheel, new rim, new spokes to your LBS that seems incapable of doing a Google search and tell them to build you a new wheel.

Your favorite mafia sucks.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [bableves] [ In reply to ]

Apr 24, 19 9:23

Post #20 of 30 (2236 views)

I was just thinking that it might be easier to just buy a complete new wheel.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [brider] [ In reply to ]

Apr 24, 19 10:17

Post #21 of 30 (2187 views)

brider wrote:

dangle wrote:

lyrrad wrote:

Any bike shop can get you a rim, that is not a rare thing.

I'm with this answer. A 20" double walled 28 hole rim is a really common BMX rim. You might have to get new spokes because it's doubtful the ERD would be an exact match, but that's not adding too much more to the cost.

Which is why I asked about the BSD of the rim. I found 2 each double wall rims in 28-hole for the 451 and 406 sizes (both are considered 20"). And that's just through JBI. I'm sure the Euro suppliers would have similar selections.

Yeah, 20" is a bit of a generic nomenclature for a bicycle rim. We don't know the whole story, but going after spoke cutting/threading and BSD seems like a pretty big step past the shop-in-question looking for a rim at all. Even if the OP couldn't get the identical BSD rim, adding a tire to the mix to salvage an entire bike shouldn't be a big deal. I'm not sure if most people would notice the difference riding slightly mismatched tires if it came to that point.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [brider] [ In reply to ]

Apr 24, 19 11:38

Post #22 of 30 (2102 views)

brider wrote:

dangle wrote:

lyrrad wrote:

Any bike shop can get you a rim, that is not a rare thing.

I'm with this answer. A 20" double walled 28 hole rim is a really common BMX rim. You might have to get new spokes because it's doubtful the ERD would be an exact match, but that's not adding too much more to the cost.

Which is why I asked about the BSD of the rim. I found 2 each double wall rims in 28-hole for the 451 and 406 sizes (both are considered 20"). And that's just through JBI. I'm sure the Euro suppliers would have similar selections.

The tire will most likely have the BSD on it. Tires normally have the metric sizing as part of the sidewall, often next to the nominal sizing, other times somewhere else on the sidewall. In this case, this 20x1.95 tire is 50-406:

"I'm thinking of a number between 1 and 10, and I don't know why!"

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [gmh39] [ In reply to ]

Apr 24, 19 13:09

Post #23 of 30 (2009 views)

I thought it needed truing (only noticed break rubbing a bit during the commute), but alas not. I guess it was probably fatigue responding to a pothole (7 years, 10-20thousand kms, including touring)

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [dangle] [ In reply to ]

Apr 24, 19 13:19

Post #24 of 30 (1990 views)

yeah, that's where I started, but they couldn't get one from the distributors, and two specialty stores (BMX and recumbent) and the country's Dahon (brand) distributor.

Re: wrenching: destroyed rear rim, frame has track style "dropouts" so no derailleur hanger, and I can't buy new rim [jimatbeyond] [ In reply to ]

Apr 24, 19 13:20

Post #25 of 30 (1984 views)

Buying with the 8 speed internal gear hub (shimano nexus) it might be a tad more expensive than I would like - especially that the current hub is working just fine

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