Dylansbob 

So I found a set of Hectres recently at the co-op and have been wanting to find a use for them. I laced up a wheelset and found nothing I had would hold them (and the frame I was hoping to use wouldn't even hold ColdeVies).

I'd bought this 531 Trek a few years ago, knowing it was super rough. The hanger was bent pretty good and had a fair bit of rust (even for me). It turned into long term seatpost extraction and fixed cup adventure. After everthing was out, I found internally it's not it too bad of condition. I didn't have a plan for it, so it'd been hanging.

After seeing enough people with nice, polished rando conversions mention the stays had been crimped, I decided to try it with the Trek. I took vise-grips and my homemade headset press and started clamping in. It went surprisingly quick, in spite of going fairly slow. I probably should have put something around the jaws, paint loss is pretty bad. It did the job perfectly though, I brought in each side by 2-3mm and now the 42c tire fits with a safe amount of room.

AJI125 

Definitely some paint loss but the shaping looks pretty good from what I can see. And nice way to get some good wider tires on there. Not bad work at all! I went with a C clamp and some shaped wood blocks and it kinda turned out more dented than dimpled...

Ex Pres 

I need to do the same with a frame I have just hanging around unused.

Dylansbob 

I had watched this video.


And thought the Trek was already so crunchy, it'd be worth a try. I was surprised how easy it was with the leverage from the visegrips. Once you've made the initial bend in the metal, it goes super quick.

due ruote 

It would be pretty simple to make a wood cradle for the outside of the stay. Drill a hole (roughly the diameter of the stay) through a piece of scrap wood, then saw the wood in half through the hole. Line with leather. I would also put some scrap leather between the nut and stay.

Senior Ryder 00 

Hi,

I need to do something similar on the outside of the chain stay on an aluminum framed MTB that I use as a townie. It's setup as a 1X and I'd like to use a larger chain ring on the middle position. Does any one think this procedure would work.

Thanks in advance.

Cheers,

Van

Dylansbob 

I would not try this with an aluminum frame. Extremely likely it would burst the tubing.

gugie 

^this^

gugie 

You can search "dimplin chainstays" and get a lot of different devices people have made. Here's my version, I had a decent sized C-clamp and some hardwood sitting around, some 1/2" square steel stock, a grinding wheel, fines, and a torch:



The piece of wood was filed and scraped to match the chainstay, and I put a shallow countersunk flat hole with a forstner bit on the backside for the clamp to set in.



I gave it a name.



As noted before, there are many ways to make a chainstay dimpler, including not making one at all, as the OP did. You want to protect the outside with something, concentrate the forces on the inside, and spread them out on the outside. Anybody with a bit of mechanical inclination will figure this out. Just start with a bit of force, check, and if you need more denting, give it a bit more. Rinse and repeat until desired clearance is done.

The dent doesn't have to be super long, as seen on many vintage bikes, and it certainly doesn't have to have a crease at the bottom. I'd avoid anything with anywhere near a sharp edge - you want to minimize creation of any stress risers on your frame.

Bianchigirll 

Oh good now hundreds of nice old frames are not only getting ‘drewed’ they are getting “Dilberted” too. #Dilberted = crimping a bike frame for fatter tires

T-Mar

I wouldn't do this just by ovalizing the stay, as you're sacrificing lateral rigidity. Dimpling/fluting sacrifices lateral rigidity too, but not nearly as much, as the flute acts like a stiffening rib, restoring much of the lateral rigidity removed by the change in section modulus.

Bianchigirll 

^. What he said!

Lascauxcaveman 

Your wordsmithery here is impressive, as usual

And yes, @gugie, you're a dad, you're allowed to make dad jokes.

xiaoman1 

This "Twice".
Ben

noglider 

This made me cringe. But maybe I'll do it to my Super Course. Oy.

scarlson 

I'd not worry. I've toured on a tandem with DIY smushed chainstays. I did them with a wooden block hollowed out to half-round, an aluminum rod, and a pair of pliers. It's held up fine under 420lbs of team plus camping gear. I've carted 250lb drunks to their homes on the back of it. As long as you don't go crazy thin, and also don't crack the chainstays, I think it should be fine.

scarlson 

I was thinking about this on my ride yesterday. On my Vitus 979, mind you - a decidedly un-modifiable bike. It's been bugging me, because I don't know why you picked Dilbert. Obviously I know the comic strip and such, but I am bad at memes and pop culture because I live under a rock, so I have to ask: why Dilbert? Will you deign to explain to this hayseed?

I am of course guilty of Dilberting, and I might extend the definition to adding tons of cheap braze-ons with a mapp torch.

gugie 

Hey, if what I'm doing is a Dilbert, I'll wear that with pride!

Over and over I see this obsession with "keeping a bike original", don't modify it, it'll on have the original paint once. Maybe we're just not talking about the same bikes. Modifying an early 70's bike boom frame isn't a sin. There are tons of them that are still OEM in the wild. Some bikes surely deserve to stay original. A lot of frames I run into are like ratty houses with good bones - they just need a refresh to be appreciated.

I've posted over and over that the number one thing you can do to make your bike ride better is to put your money in the tires, and the fatter, suppler tires you install, the better the ride. If you need to dimple the stays to provide enough clearance, what's the problem?

jackbombay

The "diving bell" cable stops are not cheap! But, oxy mapp or nothing.

52telecaster

i agree completely, i just dont have the guts to dimple. My next 650b conversion will be an old falcon with 531 straight guage and huge clearance.

scarlson 

Ehh, thems fighting words! I use MAPP/air or oxy/propane and it's all just fine. Cheaper too!

Guess I am a dyed-in-the-wool Dilbert. I still want to know what the reference is! Or for that matter, who on earth is Drew?

Charles Wahl

I suspect that "Drew" was the now-unknown Ur-Mensch who gelded all the braze-ons and derailleur hanger off his Colnago or Jack Taylor to make it a fixie, and posted it on a forum. With enough research (maybe this could be a modern-day PhD project) a picture of his grinning face might be found.

jackbombay

The oxy cylinders run out right quick, thats for sure, but with MAPP/air it seems it takes forever to actually get silver to flow, I'd rather spend more on oxy and have the steel hot for a much shorter period of time than spend so long with the MAPP air, that is at 6,200' in Idaho, maybe MAPP/air runs hotter at sea level?

gugie 

Hmm, I have a lot of them, paid under a dollar each on average. I’d be happy to share...even at retail you can get them at framebuildersupply.com for tree-fiddy a pair.

scarlson 

Good point, all my experience is in Medford, 14ft above sea level. Also we've probably got different torches. Mine's one of the old-fashioned swirl flame things that howls terribly. Most small silver jobs, like decaleurs, I can get away with propane/air using that torch. With mapp/air I also used it for bronze brazing a few times and it seemed all right albeit somewhat slow.