Tandem Tom

I have 26" Velocity AeroHeat rims that I am preparing to drill out to fit Schrader valves. I contacted Velocity to get their input/caution and they said "no problem" to do this.
Would like to know what the best procedure is to drill and the "finish" the hole. Reaming?
The reason for the change is these wheels are on our touring bikes and I want to have options for both Presta & Schrader.
Thanks!

TiBikeGuy

Done that before, use a 10 mm drill bit and slowly ease the drill bit into the valve hole. After use a small round file to remove any burrs or sharp edges.

Retro Grouch 

I use a tapered reamer for doing that.

Tandem Tom

When using a reamer do you use it by hand or with a drill?

FBinNY 

The tool of choice is a T-handled tapered reamer. As the T-handle implies it's a hand tool, not a power tool.

If you prefer drilling, the size is a letter N drill, or the closest size bigger, which is 5/16". This is the right size for SV that are threaded all the way down. For those with a conical rubber base (most common these days) you want to go a bit bigger, maybe 9mm or so.

Bill Kapaun

21/64".

You could get a Schraeder/Presta adaptoer.
I keep one on my key chain.

Reynolds 

I wouldn't use a power drill, it can snag on the rim. Better to use a hand reamer or even a large round file, then some sandpaper to soften sharp edges.

seedsbelize 

I've always used a chainsaw file. That said, I've always had chainsaw files on hand. Doesn't take much time or effort on an aluminum rim.

RandomTroll

I drill it out with drill bits held in my hand using the smallest that won't fit then the next 1/64th larger, etc. I think this is the gentlest and least likely to leave a nick or burr.

I have been stuck in the middle of nowhere (Vidal, Colorado, to be specific) on a multi-month trip. Prestas used to be (still are?) hard to find.

seedsbelize 

With a schrader sized hole, you can use either type of tube. I was one stuck in the middle of nowhere due to my own stupidity. Took along a schrader valved tube for a presta only rim. and trashed my initial tube.

FBinNY 

One thing that people rarely consider is the clearance inside the tire at the bead. Narrow tires, combined with tires that are a bit wide at the bead line, means very limited clearance at the bead line. While there's rarely a problem drilling rims out, folks using very narrow rims may find that they cannot mount tires when using Shrader valves.

rydabent

On the other hand you could just stay with presta tubes.

HillRider

The problem, as detailed above, is that you can't always find them. Typically, Presta tubes are available only at bike shops and a lot of small towns won't have anyplace that sells them. Your advice is good if you can plan where and when you have your flats.

cyccommute 

If you are anywhere near a Walmart, you are near a source of Presta tubes. And, since you are almost always near a Walmart in the US, you are near a source of Presta tubes. YMMV in other countries but not in the US.

Tandem Tom

I started this thread and did this project this afternoon. I posted in the Touring Forum.
Thanks for all you replies!

konabunny

Maybe in the US Walmarts, but the here in Quebec the Wally worlds only cater to the mass market " bike as a toy" crowd. Don't ever hope to find a Presta valve tube here!

FBinNY 

But, T-handled tpaered reamers are pretty ubiquitous, either at tool/home super stores, or local hardware stores. So you can cross the convert to Shrader valve bridge if/when you come to it.

Anyway tubes are easily patched, so if you start out with 2 spares, the odds of running out are fairly low. When you're down to only one spare tube, plan on picking up the replacement at the next opportunity.

Thumpic

+1......

zukahn1 

+ Valve adapters cost about a $1 at nearly any bike shop and a tube costs $4.00 so you dont realy need to go to the extreme of drilling a rim. Just buy an extra tube or two and keep them with you on long rides. Most serious C&V Guys keep at least one new tube with them when riding any serious distance.

ksisler

SB - Although most of we riders have had a "lessons learned" event at one time or another, I can't say that many would draw the immediate conclusion that the right response is to start drilling out the holes in otherwise good rims. Maybe a better answer would be to be more diligent in planning your kit for the next ride... and checking it twice (couldn't resist that given the time of year). Imho, schraeder tubes have one good use; That being to make bungie cords out of them. Adapters to convert wheels to Presta are readily available and cheap...so just chuck the automotive tubes???

seedsbelize 

Yes to all of the above, as long as you live in the developed world. Schrader valves are the dominant valve here, and it's easier to buy 28" tires(true 28s) than to buy 700C. That's changing some now, but it takes time. Recently my favorite lbs began offering 700C tires in wider, knobbier sizes; unfortunately they offer neither tubes nor rims/wheels to go along with them. I can buy a normal 700 x 25, or a 700 x 2.1; nothing in between. The tires are 700 x 40. Freewheels are more common than cassettes, rod brakes are common, and on and on.

FastJake

What's wrong with Schrader valves? Hundreds of millions of cars use them, and how many failures do you hear about? The cores are replaceable (not always the case with Presta) and the presta to Schrader adapters suck. IME the adapters barely work, if at all. Why convert when you can have the better valve to start with?

Properly manufactured, presta tubes are fine. The problem is all the cheap ones that are out now, that will either fail where the valve meets the tube, or the valve itself will stick to the point that air can neither be added or removed from the tube, rendering it useless. IME Schrader valves are completely immune to this nonsense.

The only reasons to use presta instead of Schrader is if the rim is too narrow to have a Schrader sized hole, or you have a deep road rim that needs a long valve stem.

Gnosis

With all due respect, I live in the US and Walmart has a limited selection of Presta inner tube sizes, so Walmart isn’t the remedy for everyone’s various tire sizes. For instance, I’ve never been able to locate a Presta inner tube at a Walmart store that fits the 26” x 2.0 street tires I use on my long distance rides. At the Walmarts in my area, all of their inner tubes for 26” tires have had Schrader valves only. This is likely attributable to the fact that all of the mountain bikes they sell with 26” tires are equipped with Schrader valves.

ksisler

[Partial QUOTE=FastJake;16320027] What's wrong with Schrader valves? Hundreds of millions of cars use them, and how many failures do you hear about? The cores are replaceable (not always the case with Presta) and the presta to Schrader adapters suck. IME the adapters barely work, if at all. Why convert when you can have the better valve to start with?
[/QUOTE]

FJ; Agreed that millions of cars use schraeder valves. However the principle reason that one hears of few relative failures is this:

1) Under reporting and generalized naming. When folks get a flat for any reason, they call it a flat tire and they put on the spare. Which ever shop fixes the flat makes it go. If the cause was a popped valve, it doesn't matter one way or the other. They just put it right, charge you and you drive away to finish whatever you originally planned to do;

2) About 90%+ of the auto tire shops require that the tire valves be replaced when new tires are installed or they will not warrantee the new tires. Period.

Depend on how tight the price competition is locally, the shop may or may not make a point of itemizing the valve replacement ($4-5 per wheel) on the invoice, but almost all of them replace the valves. They know that valves fail regularly and if they don't force a valve replacement then percentage wise many more tires will end up going flat and being returned to them, which damages the shops reputation and wastes time. Flatted car/truck tires are often ruined when they flat and the shop will have to eat most or all of the cost of the replacement tire even if the OEM had a 100% Road Hazard package, etc.

Besides being a 45 year bike nut, I am also a car nut, a old car restorer, a hot rod builder, and a previous auto shop owner. For sure I own antique tires/wheels from the 1930's which still have the original tubes with Schraeder valves them. But that is an incredibly rare situation (just required for max points at a Concours car competition) and I sure as heck am not going to actually drive on them.

And to close on other comments; Yes, if one lives in a developing country or any other place where XX valve is the norm, then for goodness sakes use XX valve based bike tubes. To do otherwise would be perhaps we should say "ill advised" rather than silly or begging for trouble.

/K

CrankyNeck

All of the technology we now have and we can't do better than presta? That's sad. Go ahead and make that hole bigger and use Schrader. I'm betting you'll be glad you did.