Trek_geek

For the last two years I have used my Trek 520 for a 20 mile daily commute to and from work (6260 miles to date). At the end of January this year I had to replace the Bontrager rear wheel (at about 5800 miles) as the rim brakes had worn the sidewall almost all the way through. I decided on a Mavic A719, 36 hole rims, DT dbl butted spokes and XT hub, build wheel. Since I was replacing the rear I decided to have the front wheel build by my local shop with a Dyno hub and the same Mavic A719 36 holes rims.

The rest of the story.

Since early February, Mavic has been out of stock on the 36 hole A719 rims. In the future, I plan to use the 520 for some light to medium weight touring.

Question: Would it be a mistake to have the front wheel built with the 32 hole Mavic A719??

jmeb

You'll be fine with a well-built 32 spoke wheel unless you are a really big person or you are carrying really heavy loads. At one point it was common to run more spokes in the back than the front, and for good reason! Most of your weight is in the back, the front wheel simply doesn't need to be as strong.

My current wheelset is 32/36 (front/back) and I've happily toured with a medium load spread all across it with no issues. And they are the first wheels I've built myself. Especially on a rim as beefy as the A719, 32 holes will be more than enough if built and tensioned well.

Tim_Iowa

What jmeb said. 36 is stronger than 32, but for the front it's not as vital.

The only problem is if you already have the dyno hub with 36 holes. Don't try to lace the 32 hole rim to a 36 hole hub.

Sounds like you're smart enough not to do that.

Nice pick on rims and hubs, btw. Should be strong and durable.

djb

wearing out your rim shows you predominantly use your rear brake more than front, but I would strongly suggest getting into the habit of when returning from a wet ride, take 1 min and wipe down the rims with an old rag to get the gritty junk that gets all over them. Keeping an eye on the pads can make a big difference as well as tiny bits of aluminum from the rim and/or little bits of gravel or whatever often gets imbedded in the pad material, really doing a number on rims.
Softer pads also make a big difference for rim life.

this really fast rim and pad maintenance will make a huge difference in reducing rim wear, simply because you reduce the amount of abrasive material that wears down the rim.
If this sort of maintenance isnt your thing, I'd very much suggest buying softer pads, such as Kool Stop salmon coloured ones, using both front and back equally at the least when braking (my front pads wear out about twice as fast as the rears as I use the front brake much more than the rear)
Another little trick is when braking and you hear that scrapey sound of gritty stuff on the rim, sometimes a few quick on-off brake applications will get the worst off and you will hear less gritty sound when you really have to brake harder.

I realize conditions vary and rider weight and braking styles are different, but to give you an idea, I have rims that last ten years and more of commuting with similar distances as yours.

down the road, perhaps a bike with disk brakes would be good for your riding conditions and wear rate (Im thinking cost here of replacing rims every 2 years)

Tourist in MSN

A lot of utility bikes were built with 32 front and 40 rear several decades ago.

When I built up a new touring bike a year ago I considered getting a lighter weight rim in the front than rear, the only reason that I did not was that I wanted my rims to visually match each other.

Sixty Fiver

Your front wheel does not need as many spokes because it carries less loads and has no dish, the 32 spoke wheel will be as strong or stronger than the rear 36 because of this.

There is also no problem using 36/36... a few extra spokes up front is not the end of the world either.

staehpj1

That seems odd and premature. Odd that the rear wore out first from braking. I know that I wear out the front first by a large margin if it is the braking surfaces that are the issue. Is it extremely hilly where you ride? Rims always last me much longer than that even in the mountains.

No, it makes perfect sense. I'd likely do that anyway even if I could get a 36 hole rim.

pdlamb

32 holes on the front should be fine.

But I gotta ask, what's the point of a 32 hole A719? Why would Mavic build a heavy touring rim to let the rider turn around and save 20 grams on four spokes? It doesn't make sense to me...

tarwheel 

If you haven't already built the rear wheel with Mavic A719s, you might want to consider Velocity Dyad rims. The Dyads are just as strong as A719s but lighter weight and available in various hole drillings. If you've already got the A719 rear wheel built, then I agree with others that a 32-hole rim should be fine for the front wheel. On most bikes, 60% or more of the weight is borne by the rear wheel, which is one reason why rear tires wear out so much quicker.

Doug64

I agree with folks that a 32 hole rim should be adequate for the front rim. However, the only spokes I've ever broken were on my 32 spoke front wheel ( about 10,000 miles on it) while on a tour several years ago. I attributed it to the work done to it prior to the tour. Three spokes broke at the nipple which leads me to believe they were twisted during the trueing process. Going off a very high curb with loaded front panniers might also have something to do with it. I have since replaced the wheel set with 36 spoke wheels.

2johns

I have a couple of new 36 hole matrix rims one 27" and one 700 located in Montana if one of them would work for you.

2johns

I have a couple of new 36 hole matrix rims one 27" and one 700 located in Montana if one of them would work for you.

fotooutdoors

Wear front vs rear is not just a function of how much you brake on each wheel. It is also a function of how much grit gets on the pads and rim. I killed my first rear rim (around 8000 miles, including commuting in the winter) well before the front wore out, and except in sketchy winter conditions, I brake harder on the front.

Back to the question at hand, like others have said, 32H in the front is fine. Depending on how you pack, 28h might even be okay, but considering your rim choice and the selection of a dyno hub, I see no reason to save that bit of weight. 32h is standard enough that, if you murder your wheel in the middle of nowhere, you will be able to find a replacement. A racing-type bike shop may not have 36h rim on hand, so I have been moving my bikes to 32h (or less on my race bike, but that is a different story), and always carry a fiber fix spoke when on long rides/tour.

Never broke a spoke on my hand-built 32 and 36h wheels, but broke several on a machine-built rear. That said, these days I carry a fairly light load (<220lbs bike+load+rider), so for some it may be a bit different equation.

djb

Good point, more junk certainly does collect on my rear rims. I really enjoy hard braking and hate the sound of grittiness on rims and pads, and find the 1min wipe job to be so effective. I have friends and family members who don't give a hoot.

Back to spoke count, my 32 spoked Tricross wheels have worked fine with about 40-45 lbs of load, but I'm light and I had the wheels properly tensioned at one point, which I figure was really key.

chriskmurray

That is a really strong rim and assuming the build is good it should be plenty strong, even if you are a heavier rider. People get very hung up on thinking you must use 36 spokes for a touring wheel. I always suggest it because on a touring bike you will not notice the weight at all an it is worth the extra security but the vast majority of the time 32 spokes is more than sufficient.

Trek_geek

WOW!!
All really good advice.

Yes I ride all year around, so the rear rim had two No. Virginia winters. They use quite a bit of both salt and sand on the roads and YES I hate the grinding sound the road slop causes. Until the hoses freeze up I try to rinse off the whole bike and both front and rear brake pads. Around here I even do it after a winter rain storm because the wet kicks up so much grit on the brakes. I also try a monthly full wash down including pulling the brake pads and cleaning out the bits and pieces of grit and aluminum. I have a "file card" with it's very fine, hard steel teeth that works great for that. I even swap my pads front to back to get more miles out of the set. I run 700x40 Clement X'plor MSO Adventure tires all winter with Planet Bike fenders so perhaps that contributes to the retention of the road grit on top of the pads

I am 6'3" and go about 210. Not a behemoth but not a light weight either.

I have emailed my shop to go with the 32 hole A719 if Mavic doesn't restock the 36. It has been a pain waiting but since I don't have any tours planned the dyno front hub has just been an option I've wanted for the future and the whole wheel upgrade was the perfect time for the "bank" to approve the process. ;-)

fietsbob

a 32 hole F. 36 hole rear is a good combo, the weightog the rider is a bit more on the rear wheel anyhow..

check into a direct import of the rim from one of the popular European sellers mentioned here .

djb

Certainly sounds like your riding conditions are just about the worst for rim life, that despite you trying your best to keep it clean. I know a fellow who rides a lot during the winter here in Montreal but at his work he can pull into an underground parking lot where there is even a hose and nozzle set up for the cyclists to clean off their bikes. I figure this is the only way not to do a number on rims with the salt and grit/sand.
I realize you have the 520 and arent likely to want to change it, but perhaps at some point if you keep on riding all year round, it really might make sense to go with a disk frame, or at least something to tempt you with at some point, given your riding conditions certainly fit the bill for the wear factor of rim brakes.
cheers

robert schlatte

I agree 32hole front is fine. I ride year round as well. But I never ride my good bikes when it is sloppy out. The snow, grit, and salt corrode more than just your nice touring rims. The elements are also play hovoc on your drive train and other components. Get a beater bike for those nasty winter days. Your good bike will appreciate it.