Dishing, centering of wheel and drop out widening

[oldie1982]

Hi guys

To get the rear hub motor wheel to fit centrally in the frame I need to add 10mm washers to the non drive side.

Firstly I’m pretty sure stretching the dropout 10mm on one side won’t cause the aluminium frame any issues right?

Secondly doing the above moves the brake calliper away from the brake disc by about 3-5mm.

Do I add washers behind the disc so it lines up with the caliper? Or

Do I dish the wheel?

Is dishing better or adding washers better?

Thanks

 

[oldie1982]

I tried 3mm washers before the disc goes on and now it lines up perfectly.

However the wheel is still not centred as I thought. Am I better of dishing it?

 

[Sturmey]

Reducing the dish (moving the rim more over to the non drive side by loosening the drive side spokes/tightening the non drive spokes) makes the wheel more symmetrical and hence stronger. I always try to reduce the dish on rear wheels if possible.
I would center the wheel if it reduces the dish. I would avoid increasing the dish on rear hub motors as it puts too much tension on the drive spokes and not enough tension on the non drive side spokes.

 

[oldie1982]

I should have mentioned it’s a cassette hub G020.

The wheel is more towards the non drive side. I would have to loosen the non drive side spokes and tighten the drive side ones.

What I’m wondering is what is an acceptable amount of dish? By how many mm?

 

[Woosh]

I should have mentioned it’s a cassette hub G020.

The G020 has OLD (dropout) of 138mm. Most bikes have 135mm dropout.
What's the dropout on your bike?
If you have disc brakes, avoid padding out the non drive side. It will affect the fitting of the caliper.

 

[Sturmey]

I should have mentioned it’s a cassette hub G020.

The wheel is more towards the non drive side. I would have to loosen the non drive side spokes and tighten the drive side ones.

What I’m wondering is what is an acceptable amount of dish? By how many mm?

It depends on many factors and especially the weight of the rider. I think the spec of your hub has approx 42mm flanges and already 5.5mm offset. Increasing the dish/offset by even 1.5mm to 7mm total results in a rim offset relative to flanges of 14mm and 28mm approx and this results in a spoke tension ratio of 2:1. One idea is to replace the non drive side spokes with lighter 14 G spokes which worked for me (my weight 90kg) in the past after breaking many spokes.

 

[oldie1982]

The G020 has OLD (dropout) of 138mm. Most bikes have 135mm dropout.
What's the dropout on your bike?
If you have disc brakes, avoid padding out the non drive side. It will affect the fitting of the caliper.

Its a 2014 Boardman MX Comp Hybrid, i havenever measured the dropouts but i assume they will be 135.

Your 100% correct, adding washers to the non drive side did push the caliper away from the mount so i had to add 3mm washers behind the disc.

 

[oldie1982]

It depends on many factors and especially the weight of the rider. I think the spec of your hub has approx 42mm flanges and already 5.5mm offset. Increasing the dish/offset by even 1.5mm to 7mm total results in a rim offset relative to flanges of 14mm and 28mm approx and this results in a spoke tension ratio of 2:1. One idea is to replace the non drive side spokes with lighter 14 G spokes which worked for me (my weight 90kg) in the past after breaking many spokes.

Appreciate the advice.

I had never trued a wheel or replaced a spoke before. I did one last week, took a few hours but it is pretty simple, just need patience.

I wouldnt mind giving the dishing a go with the wheel mounted in the bike.

I think i will go back to the drawing board. I am going to remove all the extra washers i put in and see how much its out of centre. Im sure somewhere i may have overlooked something as i had a 101 things to do at the same time.

 

[Sturmey]

Take a similar photo but from the drive/cassette side. I usually try to space the wheel to get the smallest outside sprocket as close to the frame as possible but with enough clearence that the chain doesn't rub off frame. Also, its possible to fit the special anti rotation/torque washer on the outside (with the tab facing in) which can be a help in some instances.

 

[oldie1982]

Take a similar photo but from the drive/cassette side. I usually try to space the wheel to get the smallest outside sprocket as close to the frame as possible but with enough clearence that the chain doesn't rub off frame. Also, its possible to fit the special anti rotation/torque washer on the outside (with the tab facing in) which can be a help in some instances.

I will remove the wheel and measure the dropouts and take a better photo as above as soon as I get time.

 

[Sturmey]

Hi. Looking at photo. The freewheel doesent look straight but it could be just the camera (or my eyes). The 10 speed needs a lot of room. Is the axle level? Even 1 mm off level will trow off the wheel by 3mm. Check that axle fits well into dropout especially on non drive side. Had you to file the dropouts? Note the new 12mm axle can leave a gap as frame is designed for 10mm axle.

.

 

[oldie1982]

Measured the dropouts 135mm

10 speed cassette.

Removed the washers and started again to see where i may have gone wrong.

I forgot to take photos but i think i may have removed more material from the non drive side dropout to get the axle to fit. Hence the wheel more towards one side. See photos. Do i file the drive side drop out a bit more to even things out?

The non drive side has tyre clearence of roughly 10mm near the chainstay and seat stay
The drive side has roughly 3mm clearence near the seat stay and 6-7mm near the chainstay

Whats going on here?

At the time photos were taken, the drive side only has 1-2mm washer between the drop out and axle so it does not foul the cassette. The non drive side has one small washer 2-3mm on the insid eof the dropout.

 

[Nealh]

Get the disc /calliper spacing correct then dish the wheel, if the rhs has to be sprung in then so be it.

 

[oldie1982]

I think I will give the dishing a go. Do I remove all washers from the axle before doing this?


Why has the wheel got different clearance from the top and bottom on the same side?

 

[Nealh]

Is the axle sittin gin the drop outs properly on both sides ?
Have you had to deepen the the axle seat at all in the drop outs ?

 

[oldie1982]

Is the axle sittin gin the drop outs properly on both sides ?
Have you had to deepen the the axle seat at all in the drop outs ?

Yes the gaps look a lot bigger in the pictures then they really are. The non drive side I did mess up a bit but the axle is in properly.

I did use a file to get the axle into the drop outs.

 

[oldie1982]

Here is a picture of another wheel I have. Looks central compared to the other. Clearance near enough the same top, bottom and both sides

I think I may have messed up doing the truing on the other wheel.

 

[Sturmey]

The non drive side has tyre clearence of roughly 10mm near the chainstay and seat stay
The drive side has roughly 3mm clearence near the seat stay and 6-7mm near the chainstay

Going on your figures above, thing are not bad. You have plenty of clearance on the non drive side, so you can move the rim over in that direction by reducing the dish.
I always do the dishing with the wheel on the bike and tyres at full pressure (with double walled rims only). This can be done later any you usually have to check and tighten up the spokes shortly after fitting the wheel anyhow. I not sure about filing any more of the dropout. Think of Father Ted fixing the car!

 

[oldie1982]

Going on your figures above, thing are not bad. You have plenty of clearance on the non drive side, so you can move the rim over in that direction by reducing the dish.
I always do the dishing with the wheel on the bike and tyres at full pressure (with double walled rims only). This can be done later any you usually have to check and tighten up the spokes shortly after fitting the wheel anyhow. I not sure about filing any more of the dropout. Think of Father Ted fixing the car!

Haha brilliant.

I dished the wheel last night. Wheel in bike with tyre and at correct pressure.

I have got it pretty much in the middle now.

I have trued it again. Seems good to me.

I don’t have a spoke tension meter. How can I tell no spokes are really lose apart from the ping test?

Secondly is there such a thing as too much dish? What problems can this cause?

Thanks