Rattling front mudguard Sprint 7

[Jeanette Morgan]

Hi everyone,

My Sprint is running well, except for an annoying rattle of the front mudguard - I've taken the advice given previously and no longer worry about odd noises, or the lights on the handlebar electric control - and trust my weekly and daily checks will ensure safe cycling - however, I've not managed to stop the mudguard rattling. Also when braking sometimes the front brake causes a sort of shuddering, the pads are still quite new so perhaps they are still wearing in. Any suggestions, if not I'll just ignore the rattle - it does not seem to be rubbing on the wheel at all.

Thanks
Jeanette

 

[flecc]

Hello Jeanette

With the mudguard ratttle, it's worth checking the tightness of the bolt that holds it's L bracket at the top to the fork. Then check the security of the fixing of the stays at the rear of the fork legs and at the mudguard end.

If the mudguard stays aren't sitting evenly either side of the tyre, one can occasionally touch the tyre side and cause the mudguard to bounce from side to side. Slightly bending the stays can realign them with the tyre and stop the rattle.

Dirt or grease on the rim can cause the brake pads to judder and vibrate. It's worth upending the bike and cleaning the rim sides with a clean cloth and a solvent cleaner like Iso-propyl alcohol, petrol or methylated spirits. If none of these are available, use a detergent and rinse it off thoroughly. You might be surprised at how much muck will come off the rim surface. If the judder persists, the pads themselves might be contaminated and it could be worth getting a dealer to change them for new ones.
.

 

[FatMog]

Hi everyone,

Also when braking sometimes the front brake causes a sort of shuddering, the pads are still quite new so perhaps they are still wearing in.

Hmmm - my sprint front brakes also go in for juddering, have done from new. I must admit, I took the less hassle approach of ignoring it and making sure I apply the rear brake first and firmest and hoping it would go away . Didn't the torq have some sort of front brake judder thing going on?

 

[flecc]

Yes, the Torq did have, though the brake levers used were involved there.

 

[ITSPETEINIT]

Rattling muguards? Juddering brakes??

Hello Jeanette, Fatmog (can hardly bring myself to type that) and Flecc:

I have just bought a new Sprint 7 (done, what? 80 miles).

Yes the Torq was (is) notorious for Front Brake Judder. Flecc gave me the hint as to the real culprit and that was the weight in the front wheel (the motor) of the Torq. The rigid front forks did not help the problem, I thought.
BUT the Sprint suffers the same problem: I've cleaned twice with Meths and Wet or Dry Paper and it's OK for a few miles but comes back again. I even scrubbed down the brake blocks with emery cloth.
Maybe there's a better brake block material out there for V-Brakes which has a calming effect on the brake arms. If I could I'd fit my Shimano Cantilever brake arms and their pads just to see (the distance between the studs and the blocks may not be the same as V-Brakes). If the next cleaning and adjustment does not do the trick I'll set them up and try that. Ah a thought: as a first attempt I could fit the pads but here again from memory they are a different stub that fits into the arm)
I did hope that Suspension Forks would be a help but they are not.

I did have another thought (Flecc). I noticed during all this fiddling about that there was quite a bit of float on the brake arms on the studs. I will measure it (feeler guage). Perhaps the few thou' shim behind the brake arms would eliminate this and correct the problem. I suppose that with factory tolerances there is a movement at the top of the V-Brake arm of about 1/4 inch, maybe more.

The mudguard rattle is also persistent on the Torq and the Sprint. I discovered quite by accident having modified the throttle so that I could take my hand off without losing drive, but when I did take my hand off the rattling was more persistent and nearly all the time on roughish roads. Presumably because there is only one hand acting as a twitch inhibitor on the handlebars to keep them firm. The bolts and nuts are all nicely tight and the stays are as far away from the tyre as they can get. When the vibrations set in the stays will move far enough for them to rub on the Tyre (Kenda 700C x 1.9 on the Torq) and (Shield - it says on the tyre: 26 x 1.9 on the Sprint). I've bought Scwalbe Marathon+ 700 x 38 for the Torq but I have yet to fit them.
A mid-stay on the front 'guards' would be of some help: only one pair is poor design - too much unsupported 'guard' length. Its a design problem since all these factors tend to come into play, one exacerbating the others.
It never happened on my Roberts Tourer with 700 wheels and a rigid front fork - the missing link is the front wheel motor.

I shall have another go at stopping the juddering brake: do everything scrupulously and spend time setting up the 'toe in'.

Whatever the result I'll post it here.
Peter

 

[flecc]

Different brake pads help Peter. Both the Clarkes MTB pads that Halfords stock, and the Avid 20R pads help, but the best I've found are the Shimano Deore MX cartridge brake pads. None are guaranteed to completely eliminate the judder when it occurs, but that is random, my Torq for example never suffering a trace of it, though the Quando did, but in that case due to a rim unevenness.

50cycles can offer a change of brake levers to Tektro ones, but even that is not guaranteed to solve the problem. Some of eZee's new models have changed to using Shimano brakes, and that's a better way to effect a cure when this occurs. The V brake studs that insert into the forks have to changed as well though, since Shimano's pattern is different.

I've got that same float on my Torq's arms that you mention Peter, but as said, never a trace of judder. I think there are many reasons acting in combinations why this can occur on these bikes, front wheel motor weight, two cross spoke wheel builds, tolerances, rim variations, brake arm suppleness, soft action brake arms etc. On some like my Torq, there's no combination acting to cause a problem. On some like my Quando, there's a single clearly identifiable cause, in that case a poor rim section join which is wider at that part so rhythmically snatching once per rotation, though that's easing as the rim wears level. But on many I think it's a combination of two or more unhappy coincidences interacting, hence the difficulty in effecting a complete cure in every case.
.

 

[Ian]

My Torq brakes have always juddered, I don't regard it as a serious problem but I am something of a perfectionist and would like to solve it. I have tried swapping all brake components, including a Tektro lever from my Sprint (which has never juddered) however the cure was only temporary, the judder returned when the new parts bedded in. I have now ordered a Shimano Deore XT V-brake with parallel linkage, I will keep you posted on the results.

There are many posts on other cycling forums about front brake judder affecting rim braked bicycles in all price ranges, it seems the problem is not limited to electric bikes with a front hub motor, and as is our experience, it affects different users to different degrees.

 

[nigel]

Nigel

DITTO guys
i have the same problem i have changed brake blocks the new ones are longer and i always clean the front rims everything else is good and tight but it makes no difference i guess i just have to put up with it NIGEL

 

[ITSPETEINIT]

Front Brake Judder

hello everyone who posted on this subject:
That's not good news when I add it all up.
I did not want to rattle 50 Cycles cage yet and thought I would persevere with spirit and abrasive cleaning.
I certainly don't want to go down the road of new components (brake arms, studs, brake levers) since they are not guaranteed (warranted) to cure the problem. New Brake Blocks may be price tolerable - thanks for that Flecc.
The width of the rim theory has some merit Flecc. I have a Digital Calliper (in mm). I will try selected spots across the width - probably all in the end but it wont be easy because the rims faces get wider apart towards the tyre.
Today is being devoted to maintenance and this problem.

Did I miss it somewhere? Have not eZee Cycles, thru' their sole distributor, identified the problem after all this time the cycles have been in production and found a cure they can recommend?

Peter

 

[redalpha3]

I've managed to escape brake judder on my Sprint 7 (touch wood!) but do have the rattling mudguard problem. I agree with Peter in that the problems seems to be due to the length of unsupported guard. It is certainly the case on the rear mudguard. I will look to jerry-rig something between the guard and the carrier and see if that helps. The front guard chatters incessantly. Isn't it amazing how irritating these small things are?

 

[flecc]

As Ian says, the judder problem isn't just confined to electric wheel bikes, and these brake problems go all the way back to the introduction of alloy rims.

In my early trade days with all bikes having steel rims, the brakes were powerful and completely free of all vices, until it rained. Then you had no brakes!

That's why the change to alloy rims which don't work as well in the dry, but do work reasonably in the wet as well.

On the mudguard, try bending each stay outwards so that they are fighting each other like the spring on V brakes. If necessary disconnect the stays to do that. That can lessen the problem if you get the balance of pressures right, though it won't stop it on every road surface.
.

 

[ITSPETEINIT]

Brake Judder and Mudguard Rattling.

Hello again all above posters:
Do you know, I think these two 'phenomena' may be linked. There's cetainly some shimmying going on up front. The cause?
I'm beginning to think it is tolerances in manufacture of various components. You've possibly seen the acceptable tolerances when choosing parts that have a VERY critical size? +/- a few thou ! Acceptable engineering maybe but when the minuses combine on the various parts (components) involved they could add up to the cause. I remember new replacement pistons in internal combustion engines being measured and matched to the cylinder bores so that the 'differences' between bore and piston were as small as possible.
Some parts would be more suspect than others.
e.g is it the forks? The torq has different forks to the Sprint so that WOULD be an unlikely source.
The brake arms: Identical on both bikes. Ah!
The headset: properly adjusted they should not pose a problem. Putting a little 'bind' onto the bearings , might help. I know motor cycles were notorious for front wheel shimmer unless the damper was effective.
In the cycle maintenance book, the stuff that nightmares are made of: head race bearing surfaces that are not set up parallel to one another - might be a lack of proper 'finishing' on the head tube ends.
Wheel Bearings: Don't let's go down that road - but the different tolerances between one bike and another (those that get it and those that don't) might be the problem (by the way I have no idea what sort of bearings the front wheel runs on). I could give them the 'kick the front tyre' diagnosis beloved of viewers of 'cars for sale'
Spoke pattern: certainly 2 cross are not as rigid as 3 cross or more. We are getting into the field of stresses here which might require proper sophisticated measuring equipment. Is 3 cross out of the question? It is not an easy matter for clever riders and traditional cycle shops to true up the front wheel of Torq and Sprint never mind rebuild them AND with another pattern.
Thinking on
Peter

 

[flecc]

I think there are many reasons acting in combinations why this can occur on these bikes, front wheel motor weight, two cross spoke wheel builds, tolerances, rim variations, brake arm suppleness, soft action brake arms etc.
.

Basically what I said in my post quoted above Peter. The bearings won't be in the frame though, as they are precision ballrace items like these on the two shafts illustrated:

eZee have tried different forks on the Torq experimentally, presumably without full success.

 

[Jeanette Morgan]

Wow thanks for all the responses and suggestions.

Obviously it's a common problem!

I'll try the simple things suggested and if they don't work - it would appear that the symptom is just annoying rather than dangerous so I'll accept it as a characteristic of the bike (and other bikes in general).

I imagine it will wear my brake pads out quicker - at which point I'll take advice on the best ones to fit as replacements.

I think the mudguards vary - my own Sprint 7 and my husband's Sprint 7 (both delivered at the same time = as replacements for the product recall earlier this year) have different fittings on the mudguards, both rattle tho!

Thanks again
Jeanette

 

[ITSPETEINIT]

Sprint Brake Judder and Mudguard rattle

Hello again everybody:

I've done the work.
Dismantled the V-Brake; cleaned the rim with Meths (twice); abraded the rim with medium glasspaper (twice): abraded both brake blocks (just once). Toed-in the blocks 0.5 mm.
Tightened the head race (slightly).
Oh! I measured the width of the rim in about 16 places and the variation was +/- 0.03 mm.
BUT: the wheel does not run very true. It has movement out of true of +/- 1.5 mm.
Another factor is that the wheel is not dished to run centrally between the front forks: it is 5 mm closer to the left hand side.

Checked out the front mudguard stays: unfortunately mine are those that have rubber shoes attached to the plastic guards that the metal stays push into and click. Simple fine tuning of the length of the stay is not possible. Adjustment seems to be effected by undoing a screw which is inside the guard and behind the stay. I passed on that, but I bent the stay which ran closer to the tyre by forcing the rubber end attachments, one up, the other down (there was very little to be gained) making it more "Z" shaped: the other I left straight. This had the effect of "shortening" the stay, bringing that stay away from the tyre (a few thou. probably).

The road test:

The brake were Judder free for about 1.5 miles and many applications. When I braked before entering my drive I just perceived a slight grabbing on/off.
I think that the brake blocks are leaving deposits on the rim and that causes the juddering where the deposit is not applied evenly.

The mudguards vibrated with every significant bump in the road and more so if I rode one-handed. But the stays did not touch the tyre. Narrower tyres (Schwalbe M.+ 35 or 38) will help in the event that they could.

Hope that helps.
Peter

 

[Dell]

Yup my Sprint too suffers from the above niggles.
Although the mudguards usually only rattle when I ride one handed for signalling etc.
The brake problem seems on mine at least to be too much play in the V brake levers.If you hold the brake on and rock the bike back and forth you can watch the levers move with the wheel.(Don`t think I fancy shimming them tho)

 

[Ian]

As I mentioned earlier I have a Sprint which doesn't suffer Brake judder or mudguard rattle despite having the usual play in the brake arms and a small amount of play in the suspension, the only parts not original are the front rim and spokes. I purchased the bike secondhand with a rim that had failed due to excessive wear on the brake surfaces. I rebuilt the wheel using a cheap secondhand rim I already had, and slightly lighter 14g spokes as as was unable to obtain 13g. I dished the wheel as centrally in the forks as my limited wheel building skills would allow and managed to true the wheel to about 1.5mm, I then went on to use the bike and thought no more of the wheel until reading this thread. I'm now wondering whether something I did has alleviated these problems, perhaps the lighter spokes allow more flexibility in the wheel or perhaps the inexpensive rim is more or less flexible or a different alloy. Unfortunately I'll probably never know as it's doubtful anyone will rebuild a wheel over a relatively minor problem with no guarantee of a fix.

 

[flecc]

It could just be your rebuild Ian. As you will have noted before, I have never suffered from the common Torq brake judder. When I received the bike the first thing I did was check the wheel build quality as I always do with new bikes, and found very variable spoke tensions on the front, although the wheel was roughly true. I therefore slackened them all off and retrued the wheel.

It seems that's the common element here, and as I mentioned above, I'm sure the wheel build type and quality play a part in this problem.
.

 

[nigel]

Nigel

Well i cant do a wheel rebuild i am not that handy so i guess that means i am stuck with brake judder why were these bikes sold to us with this problem also nobody seems to really know what causes it ie forks brake blocks wheel rim headset and so on

 

[Ian]

I therefore slackened them all off and retrued the wheel.
.

And I thought I was a perfectionist! . Seriously though, the spoke tensions on my Torq (Which does judder) do vary, but the wheel is very true. As I'm very much an amateur when it comes to wheel-building I'm reluctant to touch what appears to be a perfectly good wheel, so I'll try different brakes and resign myself to regular rim cleaning, which does effect a temporary cure.