J_Climacus 

Well, I was really excited about this frame, but I just got it stripped down to rebuild and noticed a quarter size dent underneath the top tube. It's Reynolds 501 tubing (84 trek 520).

I'm shocked I didn't notice it before. I've been staring at this bike for.months planning the rebuild so part of me suspects I somehow did this while I was removing the headset today. Then again, it's on an area that's painted over with touch up paint or nail polish, so they could have tried to paint over the damage before, or maybe the paint is covering rust which weakened the tube and being in the stand applied enough pressure to crimp it.

Does anyone have an opinion on if this dent is fatal and/or a safety concern? If I take it to a shop and ask I'm pretty sure they will just tell me not to ride it because they don't want to be held liable. But you, internet patron, do not have that concern, so give it to me straight and tell me if you'd still ride it

sweeks

Looks like it's been there a while, and it's a steel frame. I wouldn't worry about it. I might clean it up and touch up the paint so it would be easier to tell if any cracks started forming, but it doesn't seem like an existential threat to me.

Koyote

A small dent like that on the TT is no big deal.

mpetry912 

I agree. what kind of frame ? or tubing? it's not a superlight tube (like 531SL)

I think it is non catastrophic. don't worry too much about it

/markp

J_Climacus 

Hey Mark, thanks for the reply. This is Cliff from CR by the way. I actually looked at some of your old posts in the CR archive before posting here. It's Reynolds 501. I don't really care about it cosmetically, I just don't want my top tube to snap in half while I'm riding down a hill

mpetry912 

Nah, it won't do that. the tube cross section has not been compromised. The top tube is loaded in compression mostly.

somewhere I'd bet there's a finite element simulation where a circular tube is subjected to a load and then the size or radial span (subtended angle) of the dent increases till it fails.

I think we'd both be surprised at how big the dent has to be to seriously compromise the strength.

these things happen. ride and enjoy

/markp

Iride01 

It's unlikely to suddenly snap apart. If it does surprise you like that, then it's because you didn't pay it any attention while a crack was developing over some unknown period of time.

As a general thing any time one is cleaning, airing up the tires or otherwise just admiring the bike, one should also look to see if somethings is different than it was before with the bike. Whether it's a dent or a part of the frame that was formerly in pristine condition.

FBinNY 

Fatal? To you or to the bike?

Seriously, and discussion of tube damage in bike frames has to start with location. There's a world of difference between a dent near the head tube, and the same dent in the middle or the opposite end. Then depth and shape matter, as does the cause, if known. A buckle or upset or dent with a sharp crease is more serious than a clean dent as might happen if the bike falls against a lamp post.

As best as I can from the photos, the dent isn't in a bad place, and is shallow enough to be ignored, except for rust potential if the paint is coming off. High end race bikes have suffered similar dents from handlebars hitting the frame, and ridden for years with no issues.

If it bothers you, fill it with some body filler, and cover with some kind of decal or trim. Or do as an old riding buddy of mine did ----- put a band aid over it.

epnnf

I wonder how it happened. I would look closely @ the rest of the frame.

Germany_chris

On my phone that looks like a rust hole, I’d strip the paint and look

JohnDThompson 

Reynolds 501: seamed, cold-drawn chrome-moly tubing. Not particularly thin.

Agreed. But here may be rust under the pain that could become a concern.

maddog34

i'd be more worried about the rust that that dent... the rust runs for quite a distance away from the dent, btw... look at the rough paint as a clue to the extent of the rust....

• 501 - Reynolds 501 was a chromium-molybdenum (CrMo) steel, seamed, butted 3-tubes tubeset that made its debut about 1983 and was available in two different thicknesses.
  • 501ATB - Mountain, All terrain, Off-road
  • 501 Magnum - Same use as ATB
  • 501SB - Single Butted
  • 501SL - Special lightweight (SL) tubeset

the above is from this wiki... https://en.wikipedia.org/wiki/Reynolds_Technology
here's a chart showing weights and tubing thicknesses from Reynolds....
https://equusbicycle.com/bike/reynold...80brochure.jpg

veganbikes

Visually ugly and should be cleaned and dressed up with some paint but not fatal. Though me personally I probably wouldn't want to ride it unless I made the dent but that is just me being me. I think it probably has been there a while and will continue to be there a while and so long as you keep a good eye on it and maybe take some photos once you remove paint and then one of it painted and then just keep doing that over the months and years and check to see if it changes you will be fine.

The rust would be my biggest concern but I would look over the entire frame and make sure there is nothing else lurking.

easyupbug 

I agree with others that rust is not good and would look for local help if possible. Your worry with a shop may be valid but we have a one man shop in Portland who can be relied on to give it to you straight even if he is out the examination time and no repairs. Also In Tucson we have a frame builder who I have seen do that for myself and others. If he thought it safe he would clean that up, fill it and try to match the paint best he can with his stash of paint for a reasonable price.

SurferRosa

Yuck. File/sand away all that nastiness between the red marks really well and follow up with naval jelly. Then take another pic.

Mr. 66

You can press a lot of that dent with a removable face place stem. If it, the clamp, is the same size as the tube. You could roll it to, but that would strip the paint.

Coincidentaly, here is just that on a trek 520 made of Reynolds 501.




Not bad from dent to ding

unterhausen

I almost never say this, but I would strip the paint from the dented area. It's about to fall off anyway. No more paint than the edges of the dent. Steel does crack from dents, and if any dent in history was going to crack, this one is it.

J_Climacus 

Thanks, all. I'm in the process of stripping the gold touch up paint to see what is underneath. So far it's actually not bad, but it's slow going since I'm trying to *only* remove the touch up paint. Not finding much concerning rust underneath at the point, but I will post pictures when that process is done, hopefully later tonight.

This is unrelated, but I'm annoyed because I overpaid for this bike ($400). I knew I was overpaying, but I hate being the craigslist guy who shows up and haggles, so I just paid the money because I knew I really wanted this specific frame with the canti mounts and I'd been looking for awhile without finding one in my size.

However, Im very annoyed with myself that I didn't do a more thorough inspection before handing the cash over. I checked everything to make sure it functioned, pulled the stem and seatpost loose, etc. But somehow missed this.

It's all good in the end and a good learning experience. Just annoying! I'll probably put a saved search back up so that if another in better shape comes along, I can ride that one without the worry and re-home this one for a great price. I bought about $1k worth of non-frame parts to go on the build so it would be a shame to put all that on a bike I always have second thoughts about riding hard, even if those second thoughts are unfounded and the bike is probably fine. Or who knows, maybe I'll get to riding it and it will never give me trouble and I will just forget eventually. Time will tell.

I'll follow up when I've stripped the paint and took more photos.

J_Climacus 

Ok, I got the touch up paint mostly scraped off. For whatever reason, they slathered the paint on there even though the damage to the paint wasn't even that bad. The bubbly texture appears to have been just paint, not rust. That or it was a Rust-Oleum type product that was applied to what was at one point rust but did it's job and kept it from spreading.

The dent does have slight creasing. Tough to get a picture of but it makes me think the dent may not roll out that well if I attempt it. I may try the stem trick mentioned above, but due to the shape of the dent I'm not that optimistic about it.

All in all, it is not as bad under the surface as the touch up paint made it appear, but I'm still bummed and may try to source a frame without a dent. This strikes me as a dent, not a ding. In the meantime I will probably build this up like I intended to, though.

JohnDThompson 

I don't think you have anything to worry about. The rust looks superficial, and the dent is far enough from the stressed area (head tube) to not be a serious concern. Steel does not fail catastrophically, and if/when it does fail, you'll have ample warning.

grumpus

I wouldn't worry about it - 501 isn't likely to crack, the top tube isn't highly stressed, but I would clean off the rust and splash some paint on it.

Harold74

Speaking as a structural engineer, I've no concern for this. We deal with a similar situation often where forklifts run into building columns.

Between the frame joints, the frame is not working terribly hard. Most of the bending stress in the top tube is located near the joints which is why the strategy of butting increasingly thin tubing together as one moves away from the joints is effective. I'm pretty confident that the dent could just as easily be a hole and it would still make little difference. And that's good because, structurally, the dent may not be a whole lot better than a hole.

J_Climacus 

This is helpful, thank you!