Can I dish the wheel to fix my wheel alignment/clearance issues?

Everything about building wheels, glueing tubs, etc.
gramsqueen
Posts: 69
Joined: Wed Jun 27, 2018 5:15 am

by gramsqueen

Hi!

Disaster has struck again on my bike build. I'm using a 2013 Hi-Mod Supersix Evo size 54.

I'm having a problem with the rear tire rubbing due to the drop outs not centering the wheel properly in the rear triangle. The wheel sits about 1.5-2mm closer to the left chainstay. Since this bike has such tight clearance to achieve its true race geometry, this is an issue.
However the light at the end of the tunnel is this, when I remove the derailleur hanger, part number KP-158, the wheel is centered in the chainstays and seatstays.
Image
effectively I deleted a ~1.5mm spacer by installing the wheel without the hanger

This tells me that if I move the rim about 1.5 mm to the right, the rim will be centered. However this will achieve improper dish relative to the hub. Is it a good idea to go ahead and dish the wheel to center it on the frame, or should I move on to another project?

Thanks

by Weenie


Jugi
Posts: 542
Joined: Sun Jun 24, 2018 8:10 am

by Jugi

Re-dish the wheel. A surprisingly small adjustment is needed at the nipples for a 1,5-2mm adjustment in dish. For some reason I have come across this issue with multiple wheels when moving them from bike to bike. Not running out of tire clearance, but it's just nice to have the rims perfectly centered.

I can't see any harm in it for the wheels. Spoke angles are not symmetric in the rear anyway.

gramsqueen
Posts: 69
Joined: Wed Jun 27, 2018 5:15 am

by gramsqueen

Since the wheel would be offset to one side of the hub, is there any imbalances in stiffness when turning left or right? My first instinct is that turning left would be less stiff just because the wheel is to the right of the centerline on the hub.

alcatraz
Posts: 2218
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

All rear wheels are imbalanced. (excluded are some single speed and so on)

Hold the chainstay/seatstay and push the rim with your thumb. You'll notice it moves further if you push it (same pressure) towards the drive side. Thats why the clearance to the brakepads/stays needs to be larger on the ds side to avoid rub. How much you ask? Just do the thumb trick and see that the rim rubs at about equal pressure. Then you have the least chance of rub when riding.

If the wheel isn't centered in the frame then dishing it a bit could only improve things. It is imbalanced before and still imbalanced after.

/a

AJS914
Posts: 3487
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

gramsqueen wrote:
Sun Aug 12, 2018 8:52 pm
I'm having a problem with the rear tire rubbing due to the drop outs not centering the wheel properly in the rear triangle. The wheel sits about 1.5-2mm closer to the left chainstay. Since this bike has such tight clearance to achieve its true race geometry, this is an issue.
However the light at the end of the tunnel is this, when I remove the derailleur hanger, part number KP-158, the wheel is centered in the chainstays and seatstays.
Assuming your wheel is dished correctly, I would take the frame to a dealer to figure out why this is happening. If it's rubbing it sound more than a tiny bit off. Maybe the wrong derailleur hanger is installed?

Cannondale didn't do some a weird dropout like Specialized did with SCS, did they?

NickJHP
Posts: 273
Joined: Wed Feb 14, 2018 2:22 am
Location: Canberra, Australia

by NickJHP

Add a 1.5mm spacer to the other side...

User avatar
pdlpsher1
Posts: 2424
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

You do not want to redish the wheel or add spacers. You want to make the adjustment at the dropouts by grinding away a very tiny amount of material. A very small adjustment will lead to a fairly large difference at the chainstays, due to the large distance between the tire and the hub's axle. Watch the following video and fast forward to the 6:30 mark. Basically you want to 'steer' the wheel to one side by very carefully removing a tiny amount of material. Every frame produced goes through this step at the factory. If you are not comfortable in doing this yourself you can take the frame to a frame builder. If you redish the wheel then that means this frame cannot use any other wheel except the redished one.

ps the material removed is on the semi-circle part of the dropout where it makes contact with the hub's axle, not on the inside face of the dropout. You don't want to touch the inside faces of the dropout.

https://www.youtube.com/watch?v=xJDea5mSUJY

gramsqueen
Posts: 69
Joined: Wed Jun 27, 2018 5:15 am

by gramsqueen

Dishing the wheel is out the window, I would like the frame itself to function as intended.

What is the preferred grinding bit for this job? Need something that won't take off too much material at once

alcatraz
Posts: 2218
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Are you sure your rear wheel is dished properly? Does turning it around in the dropout move the rim sideways? (Don't forget to clamp it before measuring)

Has it crossed your mind that it's perhaps intentionally designed to have more clearance on the right than on the left? I'd ignore the stays with issues under 2mm. I'd look at the brake caliper axle and see if it's centered.

/a

gramsqueen
Posts: 69
Joined: Wed Jun 27, 2018 5:15 am

by gramsqueen

Hi alcatraz,

I've gotten the wheel dished at one shop and then checked in a truing stand at another, both sources confirmed it was perfectly trued. It's been a long week with this one

The stays on this bike do in fact have asymmetrical shapes, but the problem is the spacing. The wheel is off-kilter/skewed obviously just not half a mm, I'm using the graphic on the seat tube partly as a guide as well.

I've given the frame to my LBS to check the alignment (entire frame as well as dropouts) and will hear back tomorrow.

User avatar
pdlpsher1
Posts: 2424
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

The amount of material and also the exact location where the material is removed is paramount. If you wish to steer the wheel to one side, say the right, you need to reshape the right dropout such that the right side of hub is slightly behind the original position. To achieve this you need to remove a tiny bit of material at the 11 O’clock position on the right dropout when viewing the dropout from the drive side. The reason for 11 O’clock is because you want the 11 O’clock position to be the new 12 O’clock of the dropout. Meaning you want to shift the highest point of the dropout slightly rearward. This movement is very minute. A 0.1mm movement will probably steer the wheel 1mm at the chainstays. Just use sandpaper and go slow. Aluminum is very soft. Alternatively you can sand away the left dropout at the 11 O’clock position to move the left hub axle slightly forward. I hope you get the idea .


Sent from my iPhone using Tapatalk

gramsqueen
Posts: 69
Joined: Wed Jun 27, 2018 5:15 am

by gramsqueen

Wouldn’t filing the 11 o’clock just make that dropout wider and thus not fit the hub perfectly like it does now?

alcatraz
Posts: 2218
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

When removing material it can never really be perfect because you are enlarging the dropout and allowing the wheel more play which is bad. However the goal is to make the wheel naturally want to bottom out slightly rearwards on the ds side. So you sand there at 11 'o clock and on the nds side you sand at 12 'o clock (or maybe 1 'o clock, seen from the ds side).

If I had to grind my dropout I'd use a dremel grind bit that is as close to the axle portrusion diameter as possible. That way I know I'm grinding away the bare minimum needed.

NickJHP
Posts: 273
Joined: Wed Feb 14, 2018 2:22 am
Location: Canberra, Australia

by NickJHP

gramsqueen wrote:
Mon Aug 13, 2018 6:09 am
What is the preferred grinding bit for this job? Need something that won't take off too much material at once
10mm file does the job well with metal dropouts, and it's easy to ensure that you're taking material off parallel to the axle by having the file pointing directly to the other dropout as you're filing. I've done this on numerous frames without problem. You need to look at the amount of adjustment required to get the wheel to be centred between the chainstays and seatstays, and depending on the amounts of each, file in the appropriate direction to make the correction you need.

If the dropouts are carbon, then a piece of sandpaper wrapped around apiece of 3/8" dowel would be better.

Svetty
Posts: 530
Joined: Thu Mar 26, 2009 11:06 pm
Location: Yorkshire - God's Own Country

by Svetty

Re-dishing the wheel is harmless and reversible. Filing the dropout runs the risk of introducing further alignement errors and will void the frame warranty......

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post