Torq Problem: Offset front wheel - sticking vee brake - fork shudder

[mithril]

Hi all,

I have a problem with shuddering forks when braking. I thought this was just a loose headset which seems to be a common problem but I've tightened it quite a few times now to no avail and I don't wish to tighten it further and risk damaging it.

A fellow cyclist noticed that the front wheel wasn't centred in the forks, but offset to the right side (as seen from the saddle). The brake pad on that side is rubbing on the rim and has dipped and worn slightly below the rim. He thought this could be causing the shuddering.

As far as I can see, it's not possible to adjust the horizontal position of the wheel.

I've tried to adjust the brakes but can't get the pad of the rim - in fact I've only made it worse now.... I wish we had disc brakes !!

Has anyone else had this problem, or is the wheel position a red herring do you think?

Thanks,
Mithril

 

[rsscott]

Hi Mithril,

can you tell me if you have the Diacompe-SE8 brake levers? If so, there is a fix for this but you will need to fill out a maintenance request on the 50Cycles website here

eZee have switched to a different kind and in severe cases of juddering, the levers may need to be swapped out.

cheers
Russ.

 

[mithril]

Thanks Russ - I've just checked and that's exactly what I've got.

I'll fill out the form as suggested.

I will be very annoyed with 50C if they've sold me this bike with a known problem... I only got it a week ago!

Do you think the wheel position is a red herring then?

 

[rsscott]

Hi Mithril,

not all bikes exhibit the problem but as a precaution eZee have switched to a different model. I don't know which shipment of Torqs has the modification, they may not even be here yet. It's worth noting that the Torq itself has gone through several iterations, the latest being full mudguards and wired-in lights. It's a little like a new car, with constant revisions etc.. I think this is a good thing as it shows the manufacturer is listening to the feedback out in the field and making changes.

I'll have a look at my bike to see the position of the wheel. I probably wouldn't worry too much, I was at the traffic lights with my old electric and a van driver behind said my wheels were out of alignment. It was only when I got home and had a good look at it that I realised that was how it was designed. The front wheel was slightly offset due to the disc brake! The important thing is your bike doesn't pull to the left/right?

 

[flecc]

Are you aware of the grub screw adjustment by the pivot on each side of the brake, mithril? These bear on springs and adjust the lateral distances of each shoe from the rim. Adjustment is by tightening one side to bring that shoe out while loosening the other side, that should balance your shoe to rim distances.

The shoe's vertical relationship to the rim is by vertical sliding in the slot and rocking on it's cupped head, the latter to allow the face of the brake block to be square to the rim in both planes. These latter adjustments are a bit fiddly to do.

Apart from the fix for the juddering, these adjustments will also have to be done for the brakes to be ok. Most new bikes I've bought have needed some attention to these.

 

[mithril]

Thanks flecc. I had tried adjusting the grubs but they didn't seem to have any effect. I'll give it another go though.

50 Cycles have offered to fit new brake levers when they arrive on the next container.

 

[Tim]

50cycles new service mechanic will be taking an in-depth look at the vibration problem experienced by a few Torqs and yours will be among the first to benefit from this attention.

Tim

 

[Ken]

Torq front fork shuddering

Besides the Diacompe SE8 brakes which are identified as the main cause of the front fork shuddering. Here are a few tips of any bike users to ensure smooth braking.

1. Off wheel alignment - Off wheel alignment is a maintenance issue that requires periodical checks on even the best brands of bikes. Off wheel is caused by uneven tension of spokes, and requires "truing" in the hands of an experienced biker or bike mechanic.

2. brake adjustment - toe-in brakes, adjusting brakes to ensure brakes when not depressed are not further than 2mm from the rim. When the brakes touch on both sides they should grip evenly / symmetrically. Starting from one tip of the brake shoe with the shoe gripping all the way as the brake levers are depressed (hence Toe-in). There are several sites on the web that teaches brake adjustment and it is not overtly complicated.


p.s. disc brakes while are known to be the strongest available type available for bikes. Needs in fact.. much more maintenance than more technical maintenance than V-Brakes. Lubrication, mineral oil, calibration, weighs more and cost much much more than V-Brakes. Having said that however, we constantly receive interest for our bikes to be fitting with disc brakes and we are currently working on having a just as powerful (or even more) smaller front hub motor to incorporate space for disc brakes.

 

[Jed]

I am very interested in a more powerful motor Can hey be retrofitted to the existing Torq ?

thanks
Jed

 

[Jaytee]

I cannot understand why the lever design for the front brake can affect the fork judder on braking. I have this problem too on a bike only three weeks old. The judder is so bad as to make the bike unsafe to ride on roads or in traffic. Surely the lever is just to apply pressure to the brake calipers. The design of the lever is surely immaterial, provided sufficient cable tension is achieved.

My problem has been reported to 50cycles and I am awaiting their comments. I have unbounded, unfounded faith that they will resolve the issue quickly and efficiently!

 

[Jaytee]

It cannot do the motor any good to be 'vibrated' with this excessive judder. I think it best not to ride until a fix has been made.

 

[rsscott]

Jaytee,

check that there isn't any play in the headset when you depress the brakes and push the bike forward and then pull back repeatedly. If there is even any slight movement in the forks this will accentuate the problem. I don't get any juddering now on my Torq and I have the Diacompe levers.

It cannot do the motor any good to be 'vibrated' with this excessive judder. I think it best not to ride until a fix has been made.

 

[flecc]

Jaytee

I accept your point about the brake levers, they alone cannot cause judder, this being due to a combination of factors that the lever design can contribute to. The brake pad material is crucial in this. A soft rubber can compress longitudinally when loaded by friction against the rim, and then with the rubbers natural tendency to rebound once the compression limit has been accelerated past, a cyclic movement is set in place, i.e. judder. The lever rigidity and general "give" can have some influence on this phenomenon.

Another approach to curing such a judder is the older practice of using hard rubber pads with friction material incorporated in the rubber. Unfortunately this can cause more rim wear, or can also lose wet weather braking efficiency, so changing the lever to achieve a solution has some advantages.

I have this judder with the Diacompe levers on my Quando front brake and intend some experiments on this, but haven't been able to make time so far.

P.S. New rims can be the agent of triggering the start of juddering. Rims are made from channel strip turned into a circle and then joined. Production rims are never perfect and until the join is worn into a smooth transition section, the imperfection of the change at the join can set the judder off. It follows that this is a problem that often gets better by itself.

 

[Jaytee]

I cannot see or feel any 'play' in the headset with brakes applied as you suggest. I have read reports of people tightening the headset. How exactly can this be done? I am aware only of the Allan key in the centre of the handlebar mount. This was loose on delivery as the handlebars were misaligned such that the bike would fit into the box. I tightened this with the key provided until the handlebars were centred and locked. Is there any other headset adjustment possible?

 

[flecc]

Hello Jaytee

To adjust the headset bearings, first slacken the two side bolts on the collar section so that it's starting to be free to move, then tighten the centre bolt, which clamps the collar section down onto the black taper surround below, in turn pressing on the bearing. Don't overtighten of course, make sure there's no jerkiness in rotation, then align the handlebars again and tighten the two sidebolts.

 

[Jed]

I noticed a bit of judder on my bike over the weekend (in betqween the rain and the wind!) so therefore I tightened the head set yesterday and now it is barely noticeable.

How often do I need to do this ?

thanks
Jed

 

[flecc]

Virtually never normally Jed. It's normal for this to be needed on a new bike as the bearings seat down and run in, and may be needed a second time sometimes, but with good components and design should be ok for years then.

 

[Jaytee]

Thank you for the info. I've done as you stated and I think there was a little play afterall. Its too wet at the moment for a test ride, but I'm hopeful!!
I've not heard back yet from 50cycles about this, but its still early days yet.
May I suggest another page in your excellent website about judder and its possible cures. It seems most owners have this or get it, and your recipe for cure with a few photos might save many heartache about this!

 

[rsscott]

Hi Jaytee,

there is a little bit of information already in the Torq FAQ but it probably needs to be expanded and adding photos is a great idea!

Thank you for the info. I've done as you stated and I think there was a little play afterall. Its too wet at the moment for a test ride, but I'm hopeful!!
I've not heard back yet from 50cycles about this, but its still early days yet.
May I suggest another page in your excellent website about judder and its possible cures. It seems most owners have this or get it, and your recipe for cure with a few photos might save many heartache about this!

 

[flecc]

Good idea Jaytee, I'll do that in the next few days, incorporating it on the Bike page. Hopefully there'll be a glint of natural light this week for the photos!