Minimum Tire to Chainstay Clearance

[fogman]

I just mounted my 2015 Bora tubulars with Vittoria Corsa CXIII 25 mm Isogrip tires. They are on a Pinarello Dogma 65.1. I rode them twice for a total of 62 miles so far. Frame clearance looks good everywhere except at the chainstays behind the bottom bracket. There is only 2 mm clearance to the left (non drive side) chainstay. I measured this with a 2 mm spacer.
I am wondering if this is going to be enough clearance as there is a potential of wheel flex when climbing and/or sprinting. I fear that it is possible to eventually wear the sidewall of the tire thin and cause a blowout.
Should I consider remounting with 23 mm tubs to give more frame clearance?

[Calnago]

Didn't I provide you some pics at one point on this. I'm sure there was more than 2mm of clearance using the new Boras with 25mm Arrenbergs. Don't know if the Vittorias are wider maybe? Anyway, for your reference again... here's the pics...




When I put them in the frame I didn't think there should be any problem. It is a legit Dogma you have, right? Not a Chinarello or anything?

And I measure the width of the Arrenbergs, when mounted to be pretty much spot on at 25mm.

Got any pics of your clearance on the bike?

[sungod]

if there is contact i'd be more concerned about the chainstay - worst case for each revolution there'd be about 2 metres of tyre passing over a small patch of chainstay, so that is where heat and erosion would be most damaging

if you're not sure, put some tape on the chainstay at the potential contact point, then see if the tape gets scuffed, if it does then time for some skinnier tyres

[Valbrona]

I think it's a case of try it and see. The amount of clearance is secondary, as long as there is absolutely no contact.

[fogman]

Here is a picture. I put some electrical tape on the inside of the chainstay to see if it scuffs the tape. It is definitely a little closer to the left chainstay. Either it is the asymmetric chainstays or the wheel is dished that way. Probably is okay. I always overthink things when trying new equipment. It is an authentic Pinarello Dogma 65.1 frame purchased from an authorized dealer that is also a sponsor of my race team.

[fogman]

So after 100 miles of testing, I have come to the conclusion that there is minimal to no tire rub on the inner chainstays as evidenced by the electrical tape not being scuffed.
Oddly, my 25mm Vittoria Corsa CXIII tubulars measure 25.5mm when inflated to 100psi, but my 23mm Conti GP4000S II clinchers measure 25mm when inflated to 100psi and mounted to 20.5mm (15c ETRTO) Shamal Ultras. A full 2mm wider than their stated size.

[Valbrona]

Oddly, my 25mm Vittoria Corsa CXIII tubulars measure 25.5mm when inflated to 100psi, but my 23mm Conti GP4000S II clinchers measure 25mm when inflated to 100psi and mounted to 20.5mm (15c ETRTO) Shamal Ultras. A full 2mm wider than their stated size.

Nothing odd about it. You can get significant variation with the same tyre on different rims on account of width, depth of tyre seat, shape of tyre seat, form of hook beads ... and so on.

Hope that those wheels stay in true.