Could low brake pads cause a shimmy during braking?

I was taking my wheels off to get the tires replaced and I've been having a shudder/shimmy during braking sometimes. Before I thought it was the steering head bearings or the wheel bearings but with further inspection I found these to be in good shape. Only thing I can think of is that the brake pads are so thin that it's causing the vibration. "Thin" as in less than 2mm of brake pad remaining on the backing plate on the inside pad (non piston side). This is on all three brake calipers. I ordered a set of EBC HH pads for the whole bike and I'm installing Michelin Pilot Power tires as well. Any and all input would be greatly appreciated.

 

How badly worn are the tyres? Could be they have bumps/flat-spots on them?

 

Horribly worn. Rear tire was about 3" square in the center and the front tire was very bumpy.

 

Could be it. In theory, it shouldn't matter now much meat is on the pads and they should wear even. Have you tried spinning the wheel to check for tight spots?

 

Smooth as silk.

 

Don't think its a warped disc then. I think it could be the tyre, before I changed mine the front end started feeling a bit crap in general. Change the tyres (which you said you were going to do anyway?) and see if it helps. Maybe do one thing at a time, that way you will know what fixed it.

 

Well, the pads are almost completely gone and the tires are shot. I've already got the Pilot Powers mounted and I'm picking up the pads locally so I should have it back on the road either later today or tomorrow. If neither fixes it I'll have to get back into the bike this weekend.

 

A cupped front tire WILL cause a shimmy/vibration. Cupping is usually caused by incorrect tire pressure or as I have found, too much time cruising down the highway and not enough time hustling some twisties.

 

+1 on the worn tire response. I've seen/ridden bikes that had tires only mildly cupped (almost impossible to see the cupping) that caused an oscillation.

I'll predict the new tires will solve it.

 

Hi All,

I just purchased Fastrax203's 1998 VFR. I live near Raleigh, NC. I wanted to post about the front end shudder when the front brake is applied. I figured out the problem last night. This bike has Galfer free float rotors, but most of the float "bobbins" or "pins" were siezed up so the front rotors were not actually floating. I used a drill and some WD40 to loosen them up and get them free again. I used a drill bit that fit kinda of snug in the bobbins and slowing spun them. Took the bike out for about 70 miles today, and the shudder is no more! The bike rides like a dream. I spent about 6 hours detailing it and adjusting the chain and lubing it. I love this bike.

 

Good on ya for finding it, and congrats on the new ride! :clap2:

 

Good to see the problem gone. But I also buy into the worn front tire causing shuddering on brake applications. And tire pressure may have some to do with it, but mine has been quite constant and the shudder has shown up on four sets of tires after a few months of riding. Two sets of Dunlops and 2 sets of Michelin PR2. I have the PR3 on now but they are still fairly new. Seeing as my riding is mostly slabbing on the freeway, there could be a lot of credibility to the statement that slabbing vs twisties could be part of the cause. But the good thing was it only showed up on braking applications and did not seem to affect the stability of the bike, regardless of how I was riding. The front tire does cup really bad though.

 

Randy, I agree there can be many causes for front end "shudder". In my case the bike has brand new tires and the steering head bearing felt smooth when I lifted the front end and moved the the wheel back and forth. I read about these type of rotors needing the "bobbins" or "pins" lubricated from time to time to make sure they have some play in them. This bike came from Seattle, so probably saw a good amount of wet weather - this could have contributed to the bobbins becoming seized. I'm just so happy I don't have to replace the $290 a piece rotors, or do a head steering bearing service

 

Good stuff. But just so you know, front end shudder is not uncommon on the 6th gens anyways. And BTW. Where I am, it is wetter than Seattle. I have not had that problem but then I guess because of constant use, things tend to stay loose. I have 132,000 km + (82,000 miles) on my 06 and still on the original battery. Never been on a battery tender and still going strong. Is that what rotors are worth? OMFO!

 

I also have a shudder in my front brakes - do the stock rotors benefit from this sort of service or is it not possible with the OEM rotors?

 

@VT - not sure what the OEM's look like, as my bike already had the Galfer rotors installed. If the OEM's are semi float or full float, then yes, you may want to check and see if the rotor has some play in it as it should. If the OEM is not a semi or full float rotor, then I'm afraid your problem may be caused my something else. If you look at my 2nd photo you will see the rotor is attached to the inner blue looking ring and is attached via "bobbins" or "pins" - they look like rivets, but are actually somewhat loose, or at least they should be... If you end up having to replace your rotors at some point, make sure to put new pads on at the same time. Old pads can cause problems with new rotors, or so I've been told. Good luck.

 

Thanks. The '96 has semi-float rotors. I read that you should spray brake cleaner on the buttons to dislodge any brake dust/etc. so that they continue to "semi-float".

I'll try that first.

From what I read, the buttons on full float rotors definitely should move, but most likely will not budge on a semi-float rotor.

 

VT, do you have any cupping on the front tire? You could also actually have a warped front rotor.

 

I'm thinking one of the front rotors is warped, but am trying this out first. Just for shits and grins to see if it helps.

My front pads were brand new at the start of the 2009 season.

I do an awful lot of slab riding, so my front tires have a tendency to cup anyways. I have a Michelin Pilot Power 2CT on the front now with about 3k on it, and it has a minimal amount of cupping to it.

 

I always try the least expensive/simplest fixes first....you might try rebalancing the front wheel after putting a few thousand miles on...it couldn't hurt.