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-   -   Narrow hub, 15mm gap too much to force? (https://www.bikeforums.net/classic-vintage/1222421-narrow-hub-15mm-gap-too-much-force.html)

WillBradley1 01-26-21 01:29 PM

Narrow hub, 15mm gap too much to force?
 
Hi there,

i just laced some wheels up for a treasured (but battered) old Benotto Pista frame, I have used a little ‘torpedo jet rear hub.

I have often not been phased by the stays being wider than the hub, is almost say alittle is preferable somehow. However this hub might be a bmx hub or folding bike hub and is considerably narrower.

There is around 8mm gap on each side so total of 16mm. My instinct is that it would still be okay? Perhaps use spacer of sorts?

but definitely something I’d be keen to hear about others experience, do not want to misalign this frame!

Ta
https://cimg9.ibsrv.net/gimg/bikefor...bd52426b5.jpeg
https://cimg0.ibsrv.net/gimg/bikefor...2ea2df30a.jpeg
https://cimg2.ibsrv.net/gimg/bikefor...386de5862.jpeg

blamester 01-26-21 05:59 PM


Originally Posted by WillBradley1 (Post 21896121)
Hi there,

i just laced some wheels up for a treasured (but battered) old Benotto Pista frame, I have used a little ‘torpedo jet rear hub.

I have often not been phased by the stays being wider than the hub, is almost say alittle is preferable somehow. However this hub might be a bmx hub or folding bike hub and is considerably narrower.

There is around 8mm gap on each side so total of 16mm. My instinct is that it would still be okay? Perhaps use spacer of sorts?

but definitely something I’d be keen to hear about others experience, do not want to misalign this frame!

Ta
https://cimg9.ibsrv.net/gimg/bikefor...bd52426b5.jpeg
https://cimg0.ibsrv.net/gimg/bikefor...2ea2df30a.jpeg
https://cimg2.ibsrv.net/gimg/bikefor...386de5862.jpeg

Assuming everything is straight use some washers or spacers.

Reynolds 01-26-21 06:04 PM

I'd say you must use spacers there.

clubman 01-26-21 06:21 PM

Hubs like that were typically 110. Is the axle long enough for the bolts to bite if you fill the gap with spacers? Can't tell from the pics.
I'd think at least 12 threads would be the minimum but I'd be interested in other opinions.

dddd 01-26-21 06:48 PM

It'll be up to the OP to determine how much spacer thickness should be added to each side, respecting the chainline and also the brake arm lining up with the chainstay.

As far as thread engagement, these being fine threads, I would expect that a reliable torque could be arrived at on the nuts with as little as six threads, but more is better and the threads should always be kept well-lubed.

The spacers should be captured by a locknut on each side of the hub, and the drive-side locknut should be serrated or toothed to prevent slippage.

I would definitely never clamp down that much on the original dropout spacing, which would put undue stress on the stays leading to likely misalignment as one side always yields first.

pcb 01-26-21 06:55 PM

I'd say in general, for a steel frame 2-3mm spread/squeeze is considered safe. Getting to 5mm is sub-optimal. More than 5mm get riskier as the distance increases. 15mm is nearing insanity.

It's not only how far you're bending the frame tubes, it's also about how far out of parallel the dropout faces will be if you're squeezing them that far. Lots of uneven clamping force on the rear axle, significantly higher chance of bent/broken axle.

So, yes, use spacers. Best solution to make like easier is to position the spacers under the axle locknuts, so they're not all loosey-goosey every time you take out the rear wheel.

WillBradley1 01-26-21 08:04 PM

Spacers on the way
 
Cheers guys, spacers on there way, 2x 6.3mm.

yes the threads can bite already, plus there will still be a few mm of squeeze.

Must say it feels like abit of a bodge though with spacers? I sense these wheels may find a new frame in the not so distant future.

oneclick 01-27-21 06:08 AM

Yes, spacers; and best to go this order:
hubrace - balls - cone-race - locknut - spacer, ANOTHER locknut, dropout.

You want as rigid as possible the connection between the dropout facing locknut and the cone-race, get those nuts *tight*.

Classtime 01-27-21 07:14 AM

Maybe the Benotto has been cold set to accept 126mm hubs so bend them back? Looks like something is missing on the drive side.

Moisture 01-27-21 07:55 AM

Don't forget to check and make sure your dropouts are aligned properly before adding equal length spacers on each side:

https://www.sheldonbrown.com/frame-spacing.html#spacing

if you go down towards the bottom, you'll find "the string method"

mack_turtle 01-27-21 08:00 AM

looks like the drive side of that axle is missing a lock nut. hard to tell.

if the hub OLD and the spacing don't match up, smashing the dropouts together will put some stress on the frame (cold setting can work) and the axle will "want" to move in the frame no matter how hard you tighten those axle nuts. here's what you need to do to make it fit and prevent the axle from slipping in the frame:

1. remove the wheel put a clamp on the dropouts, squeezing them together gently. measure the distance between the dropouts (track ends) when they are parallel. you want the axle OLD to be the same as the space between the dropouts when they are parallel to prevent the hub from twisting in the slots. most likely, the spacing will be 110mm (bmx/ coaster brake), 120mm (track), 126 (old road standard) or 130 (conventional road standard). I'm not familiar with that bike, so you'll have to measure.

2. if the dropout spacing when parallel is not within ~2mm of the hub OLD, you'll want to add some spacers to the axle to make it match. I recommend removing the lock nut from each side, one at a time, and add a spacer inside the lock nut, then reinstall.

my guess is that it's a 120mm frame and a 110mm hub, so a 5mm spacer on each side will make it wide enough.

I'm still stuck on the drive side cone nut that looks like there's no lock nut.


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