shlammed

Does anyone run staggered tire sizes front to rear?




Im considering it on my new tandem build but I don't want to negatively impact the handling of the bike.


My whiskey fork recommends no larger than a 28c tire and my frame can fit a tire probably up to ~35-38c. I would only do one step up if I did stagger 28c/32c for comfort.




Any experiences are welcome.

jnbrown

Shouldn't be a problem at all. I used to run 23F/25R, now 25F/25R I like skinny tires.

zonatandem

Not an issue!

StephenH

On my single bike, I've been running 25mm front and 28mm rear, and can't really tell the difference. (28mm was not as readily available, is how I wound up with a 25mm on there.) So I'd say no reason to avoid it if you see some advantage.


On longer rides, we normally carry a spare tire, but it's smaller than the tires we ride anyway (ride 32mm, carry 28mm spare).

Pic

Last year my buddy said, "your running two different tire sizes!".
I forgot a year earlier I didn't have a matching 25mm. So on a 28mm went.
So front 25, back 28.
Still have not noticed a difference.

nfmisso

Think about the load that each wheel carries; on a tandem it likely to be much closer to the same than a single. And on many tandems, where the captain is heavier (to much heavier) than the stoker, the front wheel will be carrying more weight.

On our tandem, we're running 38's front and rear. On my singles with 559 rims, I run 32 on the front and 40 on the rear; the ones with 590 rims have f28/r37 and the 622 rims have f28/r35.

FBinNY 

First of all for the OP, there's no reason not to mix tire widths, and it's done all the time for all sorts of reasons. In your case, the fork limits the front tire width, but that's no reason to let it limit the rear, so feel free to go wider up to the max for each tire if you wish.

As for weight distribution, most is carried on the saddles and/or the bottom brackets, so even on a tandem, there's a significant shift to the rear. That's true even if the captain is heavier, though an extreme differential may cause the front axle to be the more loaded one. (anyone who knows some very basic algebra can find a sketch of a tandem, mane a few measurements to get a decent estimate of the weight distribution, and calculate how much heavier the captain would have to be to get equal loading, but I'm not going to).

The simple fact is that regardless of the weight distribution, the front wheel is far less loaded in practice, especially on bumpy roads. When approaching an obstacle, a quick flip of the wrists will swing the front wheel around it, but it has to be brought back on the far side to keep the bike upright, and because of that the rear wheel will tend to get the full impact. It's possible to bring both wheels around, but only from a greater distance, or with a more aggressive maneuver. Making it worse, the captain is fully aware of the timing, and can help the bike, but the stoker doesn't see the obstacle and even if warned won't have the timing right.

So, with respect to nfmisso's advice, most people could use more tire in back even on tandems, and the only reason bikes are normally outfitted with the same tires front and back is convention. If not for that stylistic convention, bicycles would, like trucks, buses, tractors, and other vehicles, use tires best suited to each axle, both in width and tread design.

reburns

I have measured F/R weight distribution on our tandem and my single, and both are essentially 40/60 interestingly enough. My stoker weighs about 80% of my weight.

With both of us clothed plus the bike and all the stuff we normally carry on our rack, in bags, water, etc., total package weight is around 350 lbs.

I agree that there is absolutely no reason to avoid mixing tire widths, but we run 700C/28 both front and rear, usually about 100/110 psi.

It's important to understand that on a bicycle, unlike larger motorized vehicles, either tire can under certain conditions be supporting up to 100% of the total weight, either through extreme braking/descending or steep climbing. Tandems are less likely to completely shift all of the weight onto either wheel, but there are times when it will come close nonetheless.

ksisler

Easy start is to set one wheel on scales with the bike against the wall with all your bags, water bottles full. Both riders mount and have someone read the scale. Then move the scales to the other wheel and repeat. The two figures may tell you if you are heavy on one end or the other which might aid in picking tire sizes. For my bikes I tend to run big on the front and bigger on the rear (in the range of 35-43mm). I find that the bit larger tire is more reliable for loaded touring. Others swear on (publically) 23mm tires for a pair of 300 pound riders with 100 pounds of gear... I ignore those posts..but do often put a couple of spare 25mm or 28mm tubes in my kit to help them out when found broken down along the road. //K