Rear Wheel...

[milky4130]

Guys PLEASE urgent help required, just recently I noticed on my road bike my rear wheel is rubbing against one of my brake blocks, this only happens when pedalling down on the right crank. When No force is applied on the pedals, it's fine but the moment I stand it's when the rubbing starts. Interim solution is to release the tension off the brakes(little lever on the side of the calliper)

 

Does anyone have suggestions to a more permanent solution??

[javadude]

Get your spokes tightened.

[Ysterman]

Jip, had the same problem on my new MTB ...

Had to rebuild the wheel in my case - so check your spokes

[milky4130]

Thanks Guys,

 

should've mentioned there is a Power Tap Hub built into the wheel.

[droo]

Check the bearings too, could be loose

[milky4130]

Was going to say, what a rude awakening to what the actual problem was.

Bike just came back from a service at Cycle Lab Northgate & I clearly stated that the rear wheel should be thoroughly serviced from bearings to spokes, next day on the training ride I noticed the problem was still there but not as bad as before the service, so yesterday on a training ride, doing intervals to the top of the Entrance to the Cable Car, after only the 1st interval, while descending about 4 spokes snapped, it was now unrideable & no spoke spanner in my tool bag, I had to hike back into town & arranged a friend to pick me up. So clearly it was the spokes, I think the rim is possibly to weak for the PowerTapHub-it is a Bontrager-Classics. 

[Johan Bornman]

Powertap hubs pose particularly difficult problems for the wheelbuilder. Because of the large hub flange (70mm vs about 35mm for say Shimano hubs), the spoke angles are much steeper where they meet the rim. This causes stress on the spokes where they bend to enter the nipple. The wheelbuilder needs to a) understand this and b) have a strategy to deal with this.

Also, this large flange hub limits your choices of rims to box sections only. Should you go for deep sections beyond say, 30mm, your troubles worsen.

You don't say where the spokes broke (they didn't snap, they broke. Snapping insunuates a tension break whilst they either broke from metal fatigue or from a stress crack) but if they broke at the elbows on the hub-side, the wheel was not stress relieved. If they broke at the nipple side, it is the spoke arrival angle that caused the problem. This has been written about many times here, complete with photos of the problem. Search here for "spoke arrival angle" and start seaching for a wheelbuilder that understands the problem.

 

 

[Weight Weenie]

Theres an easier way, just let Johan build your wheels from the start

[milky4130]

Thanks Johan

 

2x at the nipple-not where the spoke enter's the nipple but the part that is inside the rim.

2x at the elbow

[Johan Bornman]

OK, then your wheelbuilder was clueless. Don't go back there.

[milky4130]

Unfortunately I bought it of "The Hub" built into the wheel already.

 

JB Which rim do you reccommend I build the PT HUB into or is Bontrager Classics ok.

 

If you were in CPT right now, I would ask you to rebuild this wheel for me. Anybody you know of in Cape Town that knows a thing about building wheels

[Johan Bornman]

You don't have much choice in available rims and one of the factors is spoke count. 24-Hole rims are very rare, 28-hole just rare, 32-hole a dime a dozen.  How many spokes in your hub?

[milky4130]

32-hole

Lotsa people says Mavic Open rims was the best for PT Hub.

[Johan Bornman]

Make that Mavic Open PRO. It is an expensive rim. I'd rather fit a DRC ST-17 that looks the same but at a third (half?) of the price. About R380-00.

 

With 32 spokes you can build a durable PowerTap wheel. If you don't want it built in  Jhb, why not contact Straatvark here on The Hub? He was one of my best students ever and lives somewhere in your city.

 

 

[milky4130]

When it comes to my traing wheel, I couldn't really care what it looks like.

 

So should I rebuild it into a DRC ST-17 Rim - about R380

Spokes

Labour

Transport to JHB & back to Cpt

Insurance

 

Any idea what this would cost?

 

Thanks for all the advice here Johan it really is good to chat to someone who knows what they are talking about.