relyt

The chainstays on a frame I have are dimpled, presumably for chain clearance. Both chainstays have identical dimples on the inside, and the drive-side chainstay has a dimple on the outside as well, which the other chainstay does not have.

Will this make it difficult to respace the frame to accept a larger hub? I am thinking of using the Sheldon Brown method of respacing with a 2x4. Will the dimples cause the chainstays to bend unevenly, or bend in the wrong place?

cs1

How wide is it now? Almost every 126mm steel frame I've encountered doesn't really need respacing. Usually, you can spread it far enough to put a 130mm wheel in by hand with no problem. Not so on a 120mm though. Good luck

Tim

relyt

It is 126mm, however the hubs that I have for it are 135mm, and I am not going to put enough money into the bike to buy a new wheelset - this is a commuter build on an old road frame, using tires from a 700c hybrid bike. I was able to score a nice road frame, with most of the other parts, except wheels and brakes, from a local guy for $35. I'm glad I got it before the fixed-gear crew found out about it.

The front fork is 96mm, but I can get that up to 100mm with a threaded rod and some nuts.

Both the fork and dropouts are very rigid and I can almost, but not quite, get my wheels into them. They stretch about 3/4 of what is needed. I am mostly worried that the rear dropouts will have weak spots and bend in the wrong place.

Moose

I would suggest taking it to a shop. They'll have the right tools and know how to adjust the stays, realign the dropouts and adjust the derailer hanger. It'll probably cost less than a new wheel and you will not have to worry about shifting issues that may arise from a misaligned rear end.

well biked

The great thing about Sheldon's method for coldsetting is that you bend one side at a time, so as long as you take your time, measure along the way, and follow the directions, you will bend each side the correct amount. I've cold set using the "all thread" method, where you pull both sides apart simultaneously and hope for the best, and I've used Sheldon's method. Realizing the difference now, I'll only use Sheldon's method in the future. You can actually end up with a better aligned frame than you started with.

Btw, the frame I ride the most these days was originally spaced at 126mm, and I cold set it to 135mm using Sheldon's method. With that much difference (126 to 135), it's worth it to re-align the dropouts in my opinion.

HillRider

How about respacing the rear wheel to 130 mm to allow it to fit in your 126 mm frame with less force? Remove 5 mm of spacers from the non-drive side of the hub, shorten the axle 5 mm and redish. All of this will cost no money and only a little time and effort.

Retro Grouch 

Yup. That's what I would do too.

Navy_Chief

I just finished cold setting a similar frame a couple of weeks ago using the Sheldon Brown method and encountered no issues. Just take it slow and work a little bit at a time, I ended up with a perfectly aligned frame going from 126mm to 135mm. No shifting issues, no issues at all actually.

Chief

relyt

Well, I went ahead with the Sheldon method, and respaced to about 130mm, and now the 135mm hub slides right in if I spread the rear triangle a little bit with my hands. Alignment is still fine, and the stays bent in the right place.

I seem to have a very, very stiff frame for a steel frame, because it was a total pain to bend even 2mm per side, I had to stand on the end of the 2x4 with both feet in order to change the spacing at all.

I am leaving my wheel in the frame overnight to make sure the frame sets right, and after that it is time to paint!

As far as the fork goes, it turns out that the spacing was easy to stretch by hand, but the slots in the fork for the axle were too small - I guess vintage axles must have had a slightly smaller diameter. A few minutes with a file, and now everything fits fine.

cs1

Still this might be workable. A lot of early MTB hubs like the Deore series had the same flange spacing as a 130mm hub. Usually, all you needed was a shortened axle to make it fit in a 130mm frame. That's all of about $6.00 for a new axle. If it was one of the later Parallax style hubs with the big dust seals, it can't be done. It might be helpful if you can post a pic of the wheel you want to use. Include a close up of the hub itself. Good luck

Tim

HillRider

You don't even need to buy a shorter axle. A couple of minutes with a hacksaw and file will give the same results. Also, I believe 135 mm Parallax hubs can be respaced to 130 mm but you will have to lose the rubber nds seal.

well biked

Just curious, but how long was the 2 x 4 you used? What model frame is it?

In regard to leaving it overnight to "make sure it sets right," don't worry about it, that's not the way it works. The rear triangle bends just aft of the seatstay and chainstay bridges, and it does it during the process with the 2 x4, etc. Once done, it's done; it's not goiing to spring back on its own. In your case, since you cold set it to 130mm, when you remove the 135mm hub, the dropout spacing will still be at 130mm.

cs1

I believe you're correct on loosing the seals. It is a shame to loose the seals though.

Tim

relyt

I didn't want to respace the axle since I have another bike with 135mm spacing and it is nice to be able to put that wheel on it if anything breaks.

The frame is a rare one, a Sentinel Horizon, which I gather was a house-brand frame made for Supergo in the 70s. It is very hard to find info on it. It is lugged steel and is just my size (56 or 57cm?), and came with a mix of Shimano and SRAM components (or at least it came to me that way), which were middle to low end components for the time. It is lighter than I thought it would be, my U-lock weighs more than the frame. And it was only $35, without wheels or brakes. The guy selling it was really into fixed-gear, and was surprised to find out that I wanted a modern geared drivetrain on it.

Incidentally, I need 65mm brake reach for the new wheels, but there is a local shop that can help me out, and BMX sidepull brakes could also work. I know I could get nice Tektros, but I don't really want to put too much money into this bike.

EDIT: The frame has a label that says it is a "tubelite butted frame", I found a little info online that said it was double-butted, which is decent. The whole thing is incredibly stiff, though, and if it weren't for the tube thickness you could trick me into thinking it was aluminum.

cs1

IMO, 126mm to 135mm is too much. In addition to respacing, you need to think about the dropouts. They will have to be bent back inwards. In a stock frame the rear dropouts are parallel to eachother. When you respace the stays, they are no longer parallal. A 4mm respace really doesn't do too much. A 9mm could give you some problems. Sheldon Brown explains it somewhere on the site.


Tim

well biked

I agree that the dropout alignment is a concern when you change the dropout spacing as much as 9mm. But that's one reason the OP should have gone ahead and cold set the frame all the way to 135mm and not just to 130mm, because then he could have the dropouts re-aligned, which is not a big deal. Also, if the dropouts are stamped and not forged, they're usually flexible enough that they "self-align" to a great degree when the QR or axle nut is secured nice and tight, so it might not matter anyway-

relyt

The dropouts are stamped, and they were a little screwed up when I got the bike anyway, but the QR does indeed straighten them out. If this bike was a higher-end frame with nice dropouts I probably would have gotten better wheels for it anyway, in the original proper spacing and size.

dwainedibbly

Understandable, but the Tektro R556 brakes are really nice if you ever change your mind. (I bought a set from Harris when they first came out.)