Uneven rim joint on Velocity Synergy

[Jim G]

Earlier this year I bought a slightly-used front wheel with a 650B
Velocity Synergy rim. The rim's welded (?) joint is very uneven,
causing a "BUMP BUMP BUMP" during braking. I have two other wheels
with Synergy rims, both of which are fine. I've already tried sanding
down the rim sidewall by clamping some sandpaper between the brake
shoe and rim and rolling the bike around with the front brake applied
to try to make the rim smoother and eliminate the thumping braking,
but it hasn't helped. I've also ridden the bike a few hundred miles,
hoping that the brake action would just wear the lumps/depressions
down, but it hasn't gotten any better. Any other tricks or ideas?

Thanks,
-Jim Gourgoutis
SF, CA USA

[Erik C]

If they are really that bad you may want to call Velocity about it.
They are a good outfit and may be able to help.

-Erik

[billiam]

Jim,

I had the exact same issue on a new Synergy rim.  I was told it was normal & just to sand it down.  It remained a bit lumpy but wore in after a few hundred miles.  Now I can't even find where it was.  Hopefully yours will even out soon.

billiam in san diego

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[pop's]

I had a rim like that and tried being subtle with gently sanding the
offending area. I too expected normal braking to eventually wear down
the irregular area. No dice on either idea. I finally got sick of the
brake "grabbing" the rim and figured the rim was just no good and
would need to be replaced.
Since I had written off the rim I took the liberty to do ONE final try
- I took some coarse 80 grit abrasive cloth and sanded the rim HARD
around the joint. I used a hand file as a backing for the sandpaper
and I sanded enough so that I was afraid maybe I had overdone it.

Voila ! No more front brake issues at all.

Sometimes you get lucky. Sometimes you gotta teach a problem rim who's
boss. I have said it before : If it's already f-cked, why not try
something at the next level - it isn't like you are gonna make it any
worse.

Good luck,
Mike in SF

[rce...@gmail.com]

On Mon, Aug 29, 2011 at 1:18 AM, Jim G <yoj...@gmail.com> wrote:
..

> with Synergy rims, both of which are fine.  I've already tried sanding
> down the rim sidewall by clamping some sandpaper between the brake
> shoe and rim and rolling the bike around with the front brake applied
>

A better approach may be to use progressively finer sand paper
attached to a good firm sanding block, and sand down the high side of
the rim only. Work back from the joint 2, 3 maybe 4 or more inches. I
did this on several rims over the years with great success.

--

Rod C

[Jim G]

Just to follow up on this -- over this past weekend I readdressed the
rim-joint problem. I removed the wheel from the bike, unmounted the
tire and tube, and clamped the wheel in a truing stand. I used a
large, broad file as a sort-of plane to file down the uneven joint on
either side of the rim. I did ten file-strokes on either side, and
then checked the width using a small C-clamp as a crude caliper. It
took longer than I expected, but I got the sidewalls true enough that
there's no more braking pulse. Fuzzy photo:

http://www.flickr.com/photos/jimg/6163258154/in/photostream

Thanks,
-Jim G
SF CA USA

On Aug 29, 12:18 am, Jim G <yoj...@gmail.com> wrote:
> Earlier this year I bought a slightly-used front wheel with a 650B

> Velocity Synergyrim.  Therim'swelded (?)jointis very uneven,

> causing a "BUMP BUMP BUMP" during braking.  I have two other wheels
> with Synergy rims, both of which are fine.  I've already tried sanding

> down therimsidewall by clamping some sandpaper between the brake
> shoe andrimand rolling the bike around with the front brake applied
> to try to make therimsmoother and eliminate the thumping braking,

[Christian]

For some reason I am just seeing this thread now. Must not haven
paying attention. In any event, I had the same problem too. Anthony
at Longleaf--GREAT shop to work with--got the wheel replaced under
warranty. It's a shame to hear of so many others with the same
problem as those reporting it on this list are likely not everyone
encountering the flaw.

Best wishes,

Christian

[Michael_S]

I guess I'd want to figure out if it's just that the weld bead did not get ground properly at the factory or if there is some misalignment of the weld joint. Certainly if it's just a raised weld bead it would be fine to file/sand the joint flush. If the rim was not aligned properly at assembly you could run the risk of rim failure if the wall thickness on the high side was reduced sufficiently. 

 

If both sides of the joint have the same look, ( no offset) then it's probably just not flushed well enough.  If you look at the inside and see some offset between the two mating surfaces, I'd toss the rim.

 

~mike

 

 

[Nick Payne]

The Synergy rims I have are pinned, not welded. Maybe the machined
sidewall rims are welded. I always get the rims with unmachined
sidewalls - I see no point in purchasing rims that are already part way
to sidewall failure...

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[Peter Weigle]

Back in the 70's-80's (pre hard anno) we often times filed, and blended rims that were a bit uneven and had the dreaded "brake pulse"...

It was no big deal, just another thing you did to fine tune your machine.

 

I can't remember anyone pulling their wheel apart to return the rim to the manufacturer, it was too much trouble. 

If you did return it  you would have to rebuild it again, or pay to have it rebuilt.

 

It was just plain easier to deal with it, and go for a ride like the original poster (Michael?) did. I was pleased to know some rider's can still do these sorts of things.

 

Most 650b rims are very strong and if anything overbuilt. The rims we cleaned up were lightweight tubular rims and even with those I never heard of anyone having a problem caused by touching up the joint.

 

I don't want to seem cavalier about this, but feel with a good hand, and some common sense, most should be able to do this job. If you don't have the tools or the understanding of how to do this, ask someone who does.

Failing that, probably best to just send it back.

 

ptr   

----- Original Message -----

--

[Matthew J]

Thank you for your thoughtful post Peter.

In a world where so many of the things we depend upon to get by and
around have become increasingly complex, the beauty of the bicycle is
its simplicity.

No one will ever mistake me for a handyman. Nevertheless I have
become relatively adept at making my bike work even when components
are not behaving as I assumed they would.

On Sep 22, 6:52 am, "Peter Weigle" <jpwei...@sbcglobal.net> wrote:
> Back in the 70's-80's (pre hard anno) we often times filed, and blended rims that were a bit uneven and had the dreaded "brake pulse"...
> It was no big deal, just another thing you did to fine tune your machine.
>
> I can't remember anyone pulling their wheel apart to return the rim to the manufacturer, it was too much trouble.
> If you did return it  you would have to rebuild it again, or pay to have it rebuilt.
>
> It was just plain easier to deal with it, and go for a ride like the original poster (Michael?) did. I was pleased to know some rider's can still do these sorts of things.
>
> Most 650b rims are very strong and if anything overbuilt. The rims we cleaned up were lightweight tubular rims and even with those I never heard of anyone having a problem caused by touching up the joint.
>
> I don't want to seem cavalier about this, but feel with a good hand, and some common sense, most should be able to do this job. If you don't have the tools or the understanding of how to do this, ask someone who does.
> Failing that, probably best to just send it back.
>
> ptr  
>
>
>
> ----- Original Message -----
>   From: Michael_S
>   To: 65...@googlegroups.com
>   Sent: Wednesday, September 21, 2011 11:10 PM
>   Subject: [650B] Re: Uneven rim joint on Velocity Synergy
>
>   I guess I'd want to figure out if it's just that the weld bead did not get ground properly at the factory or if there is some misalignment of the weld joint. Certainly if it's just a raised weld bead it would be fine to file/sand the joint flush. If the rim was not aligned properly at assembly you could run the risk of rim failure if the wall thickness on the high side was reduced sufficiently.  
>
>   If both sides of the joint have the same look, ( no offset) then it's probably just not flushed well enough.  If you look at the inside and see some offset between the two mating surfaces, I'd toss the rim.
>
>   ~mike
>
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[Peter Weigle]

Matthew,
You're welcome.
I meant to mention, one of the best things about trying to problem solve,
and be "hands on" at home, is you'll be that much better for it out on the
road should some mechanical problem crop up.

(I've met rider's out there with expensive bikes, that don't even know how
to change a tire...)

I applaud anyone who thinks it through and can do for themselves!

[Anthony King]

I'd echo what Peter said about not stressing about a little sanding to
correct a rim joint. You'd have to be very ham-fisted to mess up the
rim when trying to even the joint. I'd venture to say you'd almost
have to set out to damage the rim.

Whether machined or not all Velocity rims are pinned and sleeved, not
welded. I carefully check all the rim joints on wheels I build. I
definitely send back any rims that have joints so misaligned they
cause me to have substantially uneven spoke tension around the joint
to built a straight, round rim. I try to catch any rims that will
cause excessive brake pulse, but have made the wrong call on a couple
of rims. I don't sand any customers' rims.

To be fair to the manufacturer and customer I try to be fussy enough
but not unrealistic. Only in heaven will rims have no seams. Of all
the rims manufacturers I work with, Velocity is the most responsive to
any problems and they always, always take care of the customer.

VelocityUSA did recently add a nice alignment table to their warehouse
and I've noticed that I'm rejecting fewer rims these days.

[Rick Johnson]

> Only in heaven will rims have no seams.

You mean aluminum rims of course, right?
I don't recall seeing a seam on carbon rims...

Rick Johnson
Bend Oregon