Pringled wheel , can it be saved?
My German Shepard plowed into the rear wheel (27X1.25) of my wife's Bridgestone at full speed . A spoke went into the RD catching between the cage and pulley and the wheel now looks like a pringle. Tight spokes , loose spokes with about a 2-2.5" variation side to side. The rim does not look bent , any chance of loosing all the spokes and being able to re-true this ?.
Last edited by Fred Smedley; 09-15-10 at 07:00 AM.
Spinning @ 33 RPM
It's possible it could be saved depending on whether the rim is bent or not. Might as well loosen all the spokes and see what it looks like.
Insane Bicycle Mechanic
Even if the rim is bent, it might be possible to save it. Loosen all the spokes, push the rim straight, true and tension as you would a normal wheel. Paying a bike mechanic to do this is usually more money than a new wheel, which is why shops don't like to do this.
Originally Posted by Fred Smedley
Best bet is to replace the rim and any damaged spokes. You will need a matched rim.
I have saved wheels like this by completely unlacing the rim. Then lay it on a glass coffee-table and check for flatness. Mark the low & high spots on opposite sides of the rim. Then lay it up against a door-frame and bend it opposite the direction of the bends. Go gently and do a little at a time and check for flatness on the glass coffee-table. When it's flat to within +/- 3mm, lace it back up into the wheel.
I tried bending back rims that were still laced but with very loose spokes but the results weren't as good. It's difficult to find the centre of the bends and to bend them in the opposite direction an exact amount.
Agree if you don't have much experience best way is that noted above, but of course very labor intensive. Up to you whether time or money is better spent. It's also critical that the rear derailleur and hanger are checked before riding again.
Yeah, the problem is, the hub itself gets in the way. One work-around is to lay the two points on the rim "around which" you want to bend it on a couple of stacks of books, bricks, 4x4 blocks, etc. I've de-Pringled a couple of wheels this way.
Originally Posted by DannoXYZ
And +1 on the derailleur/hanger check. It's unlikely both came out unscathed.
How's the dog?
I would relace it with new spokes and probably get a new hub if it's destroyed. Check the rim's sides by laying it on a nice flat and solid surface. Inspect both sides. Also check for any cracks anywhere on the rim, especially nipple holes and the valve hole.
If you have no intention to invest your time, get a new wheel instead, it's probably cheaper that way.
My adventures with tacoed wheel date to the '70s when rims were lighter and
less likely to be alloy. It was easy to pop those rims back in shape by laying
the rim flat with the 'low' parts supported by 2x4 or 4x4s and putting ones
hands on the high parts and giving a good shove down. The rim would pop back
into essentially flat configuration and you then rebuild. Best to loosen all the
spokes before doing this. You don't really try to bend it so much as pop it from
one state to another. With current rims the force required might be considerably
greater as they weigh 250-350 grams more than the ones I was dealing with and
likely are stronger alloy to boot. You might have to find a 300# person to help out.
If the wheel really is pringled/tacoed then it should have a smooth curve with 4 lobes
two up and two down at 90D intervals just like a pringle chip. It the rim has any dents, divots or rough spots on the braking surface it is best discarded as braking will be funky, but dogs are pretty soft and this is not likely. Wheel should be salvageable.
Thanks everybody for the advice. I ended up loosening all the spokes , and then used the bench to straighten the wheel as much as possible. I gradually re- tensioned and stress relieved a bunch of times and got the wheel back to 90-95% of what it was in the truing stand. Road test went well maintaining trueness and roundness. A slight tweak to the RD arm put everything else right so all is good in cheap freakville..
Last edited by Fred Smedley; 09-20-10 at 03:10 PM.