777funk

I can't see any advantage (fill me in if I'm wrong) to using Presta valves. They leak down about the same from what I can see and still develop pin hole leaks at the stem base just like anything else.

So for me, it just presents a headache when using an air compressor or car inflator.

Would I be an idiot to drill out a 20 year old Trek's Bontrager rims?

soyabean

I'd enjoy SV more if they also had that collar to stop the valve from hiding back into the rim every time I use my Park Tool INF-2.

I honestly don't think one is better than the other, I believe PV is actually necessary for thin rims, as SV holes just remove too much integrity and may make the wheel harder to keep true.

XxHaimBondxX

Not saying I did that, but if I did it to my hybrid with pretty wide rims, I'd never tell anyone.

squirtdad

Lot easier to just get presta to schrader adapters

I have found presta better for on the road repairs.... and in general prefer them...but to each their own

https://www.amazon.com/s?k=presta+to...f=sr_nr_p_72_1

cranky old road 

^ Beat me to it. Easier and safer to use an adapter when a Presta pump is unavailable? https://www.amazon.com/Presta-Schrader-Converter-Bicycle-Adapter

SurferRosa

For me, presta valves are enormously easier and quicker to inflate to a specific number. Plus, they don't look like they belong to a bso from 1970.

dedhed

I just keep some of these in the air tool drawer of the tool box. NO big deal to screw on.

​​​​​​https://www.amazon.com/Bike-Bits-Bra.../dp/B07DN2MTKQ

frdfandc

Depends on the width of the rim. If it's a narrow rim from a road bike, just use an adapter. Drilling the hole larger can compromise the integrity of a narrow rim if the hole is too big. However on bikes with wider rims like a MTB or a hybrid, drilled out many holes to accommodate the schrader valve without issue.

Bill Kapaun

+1.
I just keep an adapter on my key chain.

t2p

I use a portable inflator exclusively to inflate the tires on our bikes

except for a 60’s Schwinn Stingray - all of the bikes have presta valves

I use a thread on adapter as mentioned in above / previous posts - takes a few seconds to thread the adapter on to the presta valve and to unscrew it after the tire is inflated

CrimsonEclipse

Drilling out will be fine.
Don't forget to debur.

RCMoeur 

Heck, I used to drill out Rigida 1320s. Shouldn't be a problem.

As the Red Occultation said above, "don't forget to debur" - last week at Recycle Your Bicycle I had a new person drill out a pair of rims and then watched his crestfallen face as metal shavings came out the valve hole as he was inflating (fortunately, no puncture).

777funk

I do have a couple of those adapters and use them when I use the 12V inflator. But I find them to be a bit of an annoyance vs my bikes with Schraders. Especially so when filling a few bikes at a time.

It doesn't help that I just bought a box of 20 Schrader tubes.

These rims are holding 32mm and 25mm tires (Trek 520 and 2120). So maybe that would be too narrow to drill. I would guess it's 1/8" or so bigger diameter.

Chuck M 

Presta stems are sexier. But I would make sure the Schrader stem is long enough before drilling the rim. The profile of some aero rims may be too deep for them.

zandoval 

When I started ridding road bikes in the 70s all the tubular tires were Presta. I just stayed with Presta as I transitioned to other bikes and tires. I would suggest ya choose what type valve you are going to go with and then just modify, if you have to, your bikes to fit your preference.

I dont see much of a significant difference between the two, however; on tubless tiers there may be big differences.

veganbikes

I wouldn't drill the rims, I would just use a proper pump. A bicycle pump can pump bicycle tires and if you do it with some regularity you really hardly have to pump much especially with a good quality pump. A compressor would be great for setting up a tough tubeless thing or if I am working in a shop pumping loads of tires per day but then I have the Park Inflator. If I am super desperate and my pump is dead and there is no shop around and the only thing I have is a gas station then I will use my adapter but I treat it like an emergency tool not a daily use tool and have zero problems.

People in general just need to understand the difference between a car tire and bicycle tire and it will make life so much easier.

Jeff Neese

Schwalbe Schrader valve stems are threaded and have a lockring.

frdfandc

Drill bit size is 5/16".

Jeff Wills

As above, you are probably OK to drill your Bontrager rims for Schraeder valves.

A friend did this on his touring bike then used Presta tubes and aluminum adapters. His reasoning was that he might need to buy a new tube at a remote gas station (or something) and he might not have a choice. A Schraeder size hole and an adapter allowed for extra flexibility.

https://www.universalcycles.com/shop...ls.php?id=7716

Chuck M 

For a 700C wheel, I would use an 8mm drill.

SurferRosa

But for 27", use a 5/16"?

I think I upset someone here once for recommending a 5/16" socket (instead of 8mm) on all my Campy cable anchor bolts. Probably the only time I ever use any SAE socket on my bikes. Some habits are hard to break.

777funk

I think I will go with the tighter tolerance of 5/16". Can't have that 0.002" extra with the 8mm hole. We're talking ultra precision rubber here with this batch of Chinese 27" 1-1/8" Schrader tubes.

Thanks for the recommendations everyone. Sounds like I probably don't need to stress over it too much one way or the other. I will probably drill for Schraders next time I have a flat.

GamblerGORD53

I've been doing it for 25 years, for 35 mm tires. Start smaller, then you file to smoothen fit and maybe need to move the hole a hair.
It is harder to find tubes anywhere for sure. Factory brand shops only allowed to stock one brand often. And another thing is the cheap ones often come 36 mm valve, fricking useless. They assume use in steel rims or something. LOL.
+1 for Schwalbe tubes, I get them direct from their warehouse. Their 40 mm valve is ok with the threads.
I still have others that used to be 48 mm.
All my rims are Dyad. NONE have any cracks, even with 32,000 heavy miles and 2 tours.

Chuck M 

I hesitated posting that lest someone take it serious and toss it as an accelerant to get this to the inevitable Presta vs. Schrader argument.

777funk

Yes... lol. I figured you were joking on the 8mm. Had to joke back a little : )