Hub/Frame spacing issues. Need the best of both worlds. Help!
 

Well, here's the dilemma. I have a 87 Rock Hopper MTB. Its a fine bike. It is spaced to 135mm in the rear. I have a Sturmey Archer AW 3 speed hub all ready to go (Just have to buy spokes so I can build the wheel) but when I did a test fitting a couple of nights ago I realized that the hub is VERY narrow at 118mm. My fixed wheel hub is 135mm. So, I either ebay the 3 speed hub and the brand new shifting bits I just bought for it, or I try to make it work.

The only thing I can possibly think of is to re-space the frame to 126mm. That would be 9mm to stretch to 135mm (4.5mm per side) and 7mm to stretch to the 118.8 hub.

Am I crazy? Is that possible? I want to be able to use both wheels (fixed/3spd) but I don't want to mess this stuff up.

Any guidance/advice/etc is appreciated!

PS- I do have a spare frame that I can use to test out spacing. Should I just try it on that?

I take it the Rockhopper frame has horizontal dropouts.

When building the wheel using the S/A hub, you should probably use spoke washers that go between the spoke heads and the flange - the old S/A 3-speed hubs have narrow flanges that don't support the spokes very well.

I don't know much about S/A hubs or how easy/hard it is to respace them, and of course you don't want to respace them too far because of increased risk of bending the axle. Hence your stated plan to space the frame down to 126mm. The worry with changing the frame spacing by 9mm is that the dropouts will no longer be parallel to each other, unless you can cold-set them as well (or have a shop do it with special tools).

Given that you're going to eBay trouble and wheelbuilding trouble, I'd say you should just get an older road frame with 120, 124 or 126mm spacing and build the S/A hub into a wheel for that bike. Not too expensive. But that's obviously more cost, time, and space in your garage or wherever.

Thanks for the info about spoke washers. I had heard they were a good idea but could not figure out why. Now, I get it.

I thought about finding and building up a different frame and having a second bike, but my wife already scoffs at the number of bikes and projects I have- I don't think it would go over that well.

The Rock Hopper *does* have horizontal dropouts (that's how its currently fixed gear). I realize that respacing will man that the dropouts are no longer parallel, but I can fix that fairly easily by cold setting them. My main thing is that I want to make sure this is a good idea before I go bending my frame with a 2x4.

I take it the frame has already been respaced at least once? Since it's an '87, I would think the bike originally had 130mm spacing, or maybe even 126mm. Now it's at 135mm, and you may be bending it again, this time to 126mm. If you do end up using the frame, I think you should give it the nickname "Gumby." :D

I don't know what the original spacing was but it had the original 6spd wheel when I got the bike and it was spaced to 135mm. I do not believe it has been respaced before.

If it's really an '87, it has been respaced; 135mm spacing didn't arrive until the very early '90's, although it makes no sense that it had a six speed hub in there with 135mm dropout spacing. Are you sure the frame's spaced at 135mm, measuring from inside-to-inside of the dropouts? Most mtb's from the '80's (with the exception of the earlier part of the '80's) had 130mm, the very earliest models generally had 126mm spacing-

Yes, I am positive its 135mm. I have an IRO 135mm fix/fix hub in it right now and it goes in without any stretching at all. I ran into another Rock Hopper owner of similar vintage and theirs was also 135mm.

My only comparison here is a Diamondback Sorrento from around 1990, with horizontal dropouts, 7-speed Shimano cassette and 132.5mm spacing.

One of life's mysteries, I guess. I've got an '89 Schwinn High Sierra and a '90 RaleighUSA with a full seven speed LX group on it, both are spaced at 130mm........timcupery's aproximately '90 bike with 132.5mm spacing makes sense, too, because it was fairly common to use "between" spacing at that time to bridge the gap between the older 130mm hubs and the newer 135mm hubs. The same thing was going on with road bikes at that time, with some frames spaced at the factory at 128mm to bridge the gap between 126mm and the newer 130mm road hubs-

OK I figured out what to do. The biggest hurdle is switching between the wheels. I can't respace the SA hub to 135mm (or even 126mm) so I will respace my fixed gear wheel. Its got huge 13mm spacers that take it to 135mm so if I just put in smaller spacers to get it down into the low 120s' then it will be no big deal to respace the frame to deal with both of them. Plus if I do it right I'll have plenty of room to add some pegs to the back axle. Then I'd just need get a shock fork.

Shocks. Pegs.... LUCKY!

My 86 RockHopper & 87? Sierra are both 126.
Same frame except weld quality.(Schwinns must have been made on Monday)
Hopper has much better componants.

My 89 Rockhopper Comp has Deore 7 sp with 130mm spacing. It is stone stock.

Now for the hub question. Leave the frame alone. IMO, sell the SA hub and use the proceeds to buy a new Shimano Nexus internally geared hub. They are light years ahead of the old SA. Sheldon Brown sells pre built wheels that might be exactly what you are looking for. Good luck

Tim

"... I have a 87 Rock Hopper MTB. Its a fine bike. It is spaced to 135mm in the rear...."

Does it have a U brake? if not, it's not an 87.

Yep, its got a u-brake mounted on the chainstays :)