Rear Wheel Clearance Issues

Discuss light weight issues concerning road bikes & parts.
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PyreofFyre
Posts: 28
Joined: Thu Apr 12, 2018 6:43 am

by PyreofFyre

Hi all,

So I’m on a custom titanium frame, with the following specs;

* Dura Ace 9000 C24 tubulars,
* Veloflex Carbons (measuring about 21.5mm @ 80 psi),

I’m keen to move up a size for the tyres, to around 25mm, but unfortunately at the current type configuration noted above, I’ve only got 4.5mm (from the non-drive-side (NDS) chainstay), but 10.5mm on the drive-side (DS) chainstay. I’m worried that moving up to a 25mm (leaving only about 3mm from the NDS chainstay) may cause issues on the non-drive-side, should the tyre deflate, be deflected due to impact, etc.

Assuming that the front and rear wheels are perfectly aligned from front to rear, currently, is there any way to nudge my rear wheel a little towards the DS? The DA9000 hubs have a washer between the lock nut and the cone - I’m wondering if there would be any potential issues by increasing the thickness of the washer?

At this stage, I’m hoping to solve this through reversible means, so not considering non-reversible options (i.e. sanding down the drive side lock nut/cone assembly, etc).

Appreciate all your thoughts and suggestions.

Have a great new year’s, and ride safe everybody.

PoF

by Weenie


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pdlpsher1
Posts: 2419
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Assuming your rear wheel is perfectly dished, the wheel should have equal amount of clearance to the chainstays. It sounds like you have an issue with the frame, particularly the rear dropouts. Because the distance from the dropout to the rim is so great, it’s not possible to have a perfect dropout alignment after welding the dropouts. To compensate for this slight misalignment the dropouts are lightly sanded to ensure the wheel tracks straight. Every bike that leaves the factory (except thru axles) has this procedure done. It takes an experienced frame builder/QA technician a few minutes to perform using a perfectly dished wheel. If you go to YouTube and search for ‘Lynskey factory tour’ and go to the end of the video you can see how this is done. I suggest you ask your frame builder to correct this problem for you.


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PyreofFyre
Posts: 28
Joined: Thu Apr 12, 2018 6:43 am

by PyreofFyre

Hey pdlpsher1,

Thanks for the quick response - but let’s assume that the option to contact the frame builder is closed (had not been a great experience for me, unfortunately).

Would there be no other option available?

Thanks again!
Tim

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pdlpsher1
Posts: 2419
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Any competent bike shop can do this work for you. Basically your problem is that the rear wheel doesn’t track straight since it’s skewed to one side. Tell the shop that you want the rear wheel to be perfectly centered between the chainstays by sanding the real dropouts. It’s a very easy task but it takes experience to do it right. Find the video on YouTube to get yourself familiarized with the procedure. You don’t want to mess with the rear wheel at all. The issue is in the frame. You can also use a dishing tool to check the rear wheel. I seriously doubt your wheel is out of dish by that much. Please report back after your frame is fixed.

Btw sanding the dropout doesn’t change the dropout horizontal distance. The sanding is done on the semi-circle area because the shape of the semi-circle determines the straigtness of the wheel before the QR is clamped down.


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PyreofFyre
Posts: 28
Joined: Thu Apr 12, 2018 6:43 am

by PyreofFyre

Wow, thanks for the insights - certainly learned something new here.

Appreciate the advice, and will have the shops take a look.

Thanks again Pdlpsher1. Hope you have a great New Year’s!

PoF

by Weenie


PyreofFyre
Posts: 28
Joined: Thu Apr 12, 2018 6:43 am

by PyreofFyre

Hi pdlpsher1,

I’ve just had a thought. If I had a mechanic sand down a portion of the crescent bit of the dropout, won’t that...

* ...allow more play at the quick release shaft?
* ...cause a tilt (when viewed downwards from the rear of the saddle) towards the chainstay with lower rim to tyre clearance?

Hope I’m not misinterpreting.

Thanks.
Tim

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