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-   -   can aluminum spread (https://www.bikeforums.net/bicycle-mechanics/233661-can-aluminum-spread.html)

litvack49 10-02-06 08:05 AM

can aluminum spread
 
I have an older trek 1500 7 speed can I spread the frame enough to fit in an 8 speed hub

well biked 10-02-06 08:29 AM


Originally Posted by litvack49
I have an older trek 1500 7 speed can I spread the frame enough to fit in an 8 speed hub

What's the current spacing between the rear dropouts? If you're wanting to go to a modern 8/9 speed freehub wheel, the hub will be spaced at 130mm. I've seen it reported on this board that it's not a problem spreading an aluminum frame by hand a few millimeters, probably something like 126mm to 130mm. Nashbar's aluminum touring frame comes spaced at 132.5mm, so that it can be squeezed out or in a little to fit either 130mm road or 135mm mountain hubs as another example.............If you're talking about permanently cold-setting an aluminum frame to a wider spread, the answer is no, you can't do it; the frame has to spread out too far during the cold-setting process to get the material to "set" at the desired spread. Cold setting is for steel frames only-

HillRider 10-02-06 08:43 AM

Check your dropout spacing. There was a period in the early '90's when Trek made their Al frames with 128 mm spacing to fit both 7 and 8-speed hubs since the same frame was fitted with both types of components depending on price point.

My '92 Trek 1420 (bonded Al frame) was spaced that way. It came with a 7-speed 105 drivetrain but a more expensive model using the same frame came with 8-speed Ultegra.

Recently I upgraded my 1420 to 8-speed and have no problems installing the wider hub with no modification to the frame.

litvack49 10-02-06 08:55 AM

The frame is spaced at 126

Flanderflop 10-02-06 09:16 AM

In general bending aluminum is a bad thing, Could you get away with it? probably. If it were me, I would stick with the gearing you have or get a new frame. tell your friends thy are weenies for needing so many gears.

TallRider 10-02-06 09:23 AM

You can safely run a 130mm-spaced 8/9/10-speed road rear hub on most aluminum frames that were originally designed with 126mm-spaced dropouts. It's only 2mm of spread at each dropout. People do this all the time, as as noted above Nashbar's aluminum touring frame is designed 2.5mm between 130 and 135mm rear hub standards (road and mountain, respectively). I wouldn't do this with old carbon frames designed for 7-speed, but people (many of them quite knowledgable) do it with aluminum bikes all the time.

litvack49 10-02-06 11:04 AM

Thanks for the help it will make a nice winter project

HillRider 10-02-06 02:44 PM


Originally Posted by timcupery
You can safely run a 130mm-spaced 8/9/10-speed road rear hub on most aluminum frames that were originally designed with 126mm-spaced dropouts. It's only 2mm of spread at each dropout. People do this all the time, as as noted above Nashbar's aluminum touring frame is designed 2.5mm between 130 and 135mm rear hub standards (road and mountain, respectively).

I agree but I'd reiterate what "well biked" posted above. Use the frame as-is and just exercise your thumbs when installing the 8-speed wheel, i.e., don't cold set the dropouts to the greater width.

TallRider 10-02-06 03:21 PM


Originally Posted by HillRider
I agree but I'd reiterate what "well biked" posted above. Use the frame as-is and just exercise your thumbs when installing the 8-speed wheel, i.e., don't cold set the dropouts to the greater width.

Yeah. I should have made it more clear that the frame shouldn't be cold-set.

litvack49 10-03-06 03:58 AM

Ok I understand it was my intention to just flex the frame rather than cold set it thanks for all your help


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