sd5782 

Perhaps the wrong place to ask and the wrong crowd too, but is a wheel with a dent or hop always “terrible”. Reason I ask is I am redoing a miyata 210 mixte for a niece that has a very localized flat spot/dent in the rear rim. I am learning and playing around with my new truing stand too.

After new cheap Kenda K35s at 70psi, I couldn’t feel anything on a shake down ride. Good enough for casual rider niece I concluded. This made me think that there are varying levels of performance that dictate the level of repair. A 23c tire at 110psi going down a mountain at 40mph with a skilled rider will transmit an out of round situation way more than a 27x1/14” Kenda at 10mph in your neighborhood.

Not trying to be lazy here, but wouldn’t the soft tires mitigate a lot of this. I’m sure as kids, most of our 26” balloon tire bikes had banged up rims and those soft tires masked most imperfections. I guess I’m just somewhat of the opinion that the repair matches the technical level of the equipment and rider. Flame away if I am way off.

guy153

How flat is the flat spot? 1 or 2mm should be fine. It's not like the road is much flatter than that at the best of times. ​​​​​

sd5782 

Flat spot is perhaps 3-4mm and localized between two spokes. Interestingly the wire bead Kendas allowed the tires to take up perhaps half of that discrepancy. Point is, I couldn’t really feel anything with a test ride. My old Schwinn Super Sport has less than perfectly round wheels too. So, is the old Russian proverb true; “perfection is the enemy of good enough”?

Reynolds 

It won't affect performance or safety IMO. But it could affect your peace of mind if you have a slight OCD streak like many of us...

big chainring 

I make due with some flat spotted wheels. Yes tires will compensate somewhat. Typically though at a flat spot you end up with a couple spokes at low tension. This can give you a bit of a squishy feel every rotation of the wheel. But you are right at speeds of 10-15 mph flat spots arent too noticeable. At 20mph then you get some rythmic stuff going on and can be annoying. Braking is the other concern. The thump thump thump of the pads on that one small flat spot.

sd5782 

Now if it was one of my bikes it would be a totally different story. This bike came to me after obviously sitting in same position for years. Chain rusted and shift cables frozen and stem 2” above minimum insertion line etc etc. All good now for her however.

I am getting more ocd, but my thought was I didn’t think I could even feel a hop on a glass smooth surface considering the tires and lower pressure. I couldn’t notice any odd braking feel either. Remember, low tech and low speeds. Under those conditions, are others tushes sensitive enough to actually feel this?

randyjawa 

Well said and I agree. Any frame or component flaw bugs me on my bikes. Even if the damage does not impact performance, the presence of the flaw impacts me and does so in a negative way.

That said, in this case, I would fear not regarding the perfromance/safety thing. I would, however, explain the situation to the young lady, indicating that should it prove annoying, you will fix it for her. My guess is she will be fine with the bike as it is.

SurferRosa

You have a truing stand? What happens if you back off all the spokes and give it a major true? Do it, man!

ThermionicScott 

Yep, it only matters as much as it matters to you. I was surprised by how bent the steel rims on my 56-year-old English 3-speed were when I actually put them on the truing stand. 35mm tires at low pressures will mask a lot of faults.

And everyone has to have a "good enough" point, otherwise the wheel will never leave the truing stand and rejoin its bike.

79pmooney

What is the rim? The old aluminum rims were of a much "softer" alloy than modern rims. It took far less impact to dent them. They also took quite kindly to being nudged back. In fact every bike shop had a tool to do just that. I'm forgetting what we called them but if you asked about a "rim straightener to pull out dents", every old school mechanic who was working in 1980 would know the tool. Probably have one. I've made my own out of wood and Home Depot fasteners.

Rims went to stronger and less forgiving alloys in the '80s and 90s. They also got deeper. Both of these changes mean that a bent rim has seen far higher stresses. Being aluminum, that second stressor (bending it back) can be a death sentence, with the death happening at a random time later. The highest end, lightest rims went to the more expensive new alloys first. A Miyata 210 is a lower end bike. I had a 1983 610. I don't remember what the rims were but I'd have no second thought about using that tool for a fairly significant dent on those wheels.

Once pulled out - the wheel won't be perfect. Work hardening means that getting the shape exactly right is near impossible but you can have a rim that rolls just fine with a tire on. Runs well through the brakes. (Some hammering and filing may be necessary.) I've ridden pulled out rims for years and replaced them for other issues (like no more sidewall from braking). The tool also often dents the inside of the rim. But those tools have "saved" many wheels over the years.

To use the tool, loosen the spokes around the dent. You need to pull the rim past round because it is metal. It will spring back some. Pull it to just past round, re-tighten the spokes, true as needed and ride. (This is a lot like both wheel-building and frame straightening. Experience and touch help a lot. Do this one and you have moved a big step along the experience line.)

Now, if you are big, strong or hard on wheels, think carefully before you do this. The wheel is compromised. But many of us get years of trouble-free use.

2fat2fly

One of these would do the trick...




picture from the web, Overland Rim Tool

sd5782 

Interesting responses. I know nothing of the history of this bike or how the rim was dented or if indeed it was worked on at that spot previously. The brake track seems smooth. Catalog pics show steel wheels for the 81 Miyata 210 and aluminum for the 310. Maybe an upgrade.



hooked rims too

As I said, I know no history but this dent is very localized on the rim.






The tool shown would do the trick I bet. This isn't like an egg shaped wheel where I could get it round with my truing stand I think. I tried loosening things and such. That tool could pull just that one area while keeping the rest in line. Brake track is smooth and consistent. Perhaps it was worked on in the past. As one can see, the flat spot is perhaps 2 1/2". When riding, I would guess with 60-70psi the contact patch is perhaps 3-4" long. My question comes from lack of feel of anything when riding and wondering if the longer contact patch masks it.

As I said if it was mine, or if it was used differently it would be a different story. I could also damage it trying to pull the flat spot out to mask the "bump" that isn't felt. As it is, I am bringing back a nice vintage bike for a novice rider. It was neglected and not operable and in need of attention. I have some odds and ends to do yet but am satisfied it will be safe and smooth.



81 Miyata 210 mixte getting upright conversion

Dylansbob 

I picked up some supercheap fixed gear wheels with extra deep section rims. The rim was so out of round at the pinning, no amount of spoke tensioning could overcome the stiffness of the extrusion. If I ran anything smaller than a 32, it was noticable. Installed some cheap 29x2 mtb tires and couldn't feel a difference.

If the bead isn't damaged, I say run it.

bikemike73 

It looks to me like a mm or 2 at the most.

I would leave as is on this bike.

I do not believe this would "pop" off the rim and should be safe for the kind of use the bike will get.

I would not even mention it to your niece. It is barely noticeable, and if you rode it with no issue, should be fine

sovende

I’m definitely going with the “leave it as is” crowd! Someone with severe OCD would prolly, at least, try to make it perfect but as mentioned early on, the enemy of good is better! No mention was made as to the interest and/or abilities RE: cycling, of the OP’s niece but I’m guessing that the use of this bike by any rider would be quite unlikely to lead to a situation where the very slight out of roundness would result in a dangerous outcome!

plonz 

The brake track looks deformed. You don’t get a noticeable brake pulsation from that? One of my Ksyrium rear wheels has a similar deformation from a railroad track. Been riding it for years that way, even with a little thump thump thump during braking. I wouldn’t use it in a criterium but not a concern with the riding I’ve done with it.

cyccommute 

That looks like an impact. No amount of tweaking the spokes is going to take it out. Nor could you pull it out. The rim walls are dented inward. If it’s unnoticeable to the rider, leave it alone. If you do feel it or if the brakes pulse, get a new wheel.

Biketiger

Definitely leave it alone. You've done a great job turning an older neglected bike into a cool and safe ride for your niece.
Why mention the flat spot? It's totally minor and in no way effects the performance. She would never notice it so why diminish her joy of a great gift. Let it be!

sd5782 

Actually the brake track is very smooth feeling. She bought the bike used years ago, so maybe a shop got it “good enough” a couple decades ago and cleaned up the track too. No pulsing at all. Those Weinmann upright bar levers I put on give a REAL strong pull on the calipers.

Thanks for all the thoughtful replies. Just a post to question if a beauty mark on an older bike may not really be a problem depending on intended use.

ThermionicScott 

After seeing the picture, I'm of two minds...

1) Yes, the wisest course of action would be to leave it alone. It's not bent enough to pose a danger of blowing off, and as you say, it can't be felt while riding and braking.

2) But yet, if it were my wheel, I'd be tempted to try pulling out some of that dent. It's nice soft thick aluminum, so it would be pretty forgiving. Those rim-dent-puller tools are really neat, but neither of us have one, so it would be wood blocks and C-clamps, after loosening up the two spokes surrounding the dent. Heck, I've used a wood block and a hammer in the past. But you should really stick with option #1...