I was wondering if anyone is riding a P-38 with a 20" front wheel and a 26" rear wheel. How much does this configuration change the handling and hill climbing ability?
Currently my P-38 has a 16" front wheel and a 26" rear and I keep thinking a 20" front wheel would smooth out the ride and maybe give me a little speed boost. Not sure about either.
Thanks.
1) What is your ex-seam? How tall are you? What size frame do you currently ride? And what size crankset do you have?
2) Some (but not all) Lightning P38 unicrown-style 16/17" forks have just enough room to squeeze in a 20" ISO 406 wheel. But only with a skinny racing tire like a Continental Grand Prix or a Schwalbe Stelvio. Try borrowing a 406 wheel and putting a skinny tire on it. See if it will fit inside your fork.
If it fits, ride it, and see how you like the "feel" of the bike. Expect it to seem strange at first. But you might grow to like the change. There is a chance of crank interference with the bigger wheel. And getting your feet flat on the ground at stops may be harder. But if it fits, and you ride it, and you like it, you can put a caliper brake on the rear of the fork. Note well: even if the wheel and tire do fit, there will be no possibility of using a fatter tire and/or putting on a fender. Strictly skinnies.
3) If the wheel does not fit in your existing fork, you will need to get another fork. Lighting can sell you a very light and nice 20" one for around $200 or so: it comes in two different versions: racing or touring. Some juvenile mountain bike and BMX forks can also be made to fit, but they will be much heavier.
4) Is the change to the larger wheel worth the expense and hassle? It mostly depends on your physical stature. Shorter riders will usually be better off with the 16" wheel, while medium and taller riders will often prefer the ISO 406 20" wheel. Some people have even tried using still larger wheels. I think Ben Fox has an ISO 451 20" front wheel on one of his Lightning bikes.
If you can get your existing fork to accept the new wheel, and you can live with racing tires only, you just need to buy the wheel, tire, tube, and caliper brake. Not a big investment.
Only personal experimentation will provide a conclusive answer.
My $.02: The 20" (406) Unicrown P-38 front fork gives you minimal tire clearance. This cuts down your choices to very a very very short list. Forget about a fender. Even with a tire that fits- The Schwalbe Durano, you can not pump the tire to full pressure without it rubbing the fork crown. The maximum pressure I can use is about 85 pounds. But this doesn't seem to effect the performance of the bike. If you hit some road debris however, it is possible for the tire to pick it up and get caught in the fork crown. This happened to me on a fast descent and I was fortunate to escape with just a nasty gauge in my tire; but my skin still intact. There are alternate 20" forks which will give you better tire clearance; but they are somewhat heavier than the stock P-38 Unicrown, and may require a different front brake. Tim offered me a fork exchange; but I'm a weight weenie, and I've decided to live with the Unicrown. If you don't mind adding a few ounce -- then switch to the heavier, more user and tire friendly fork design.
I have a 20/26 P38. Though it was purchased new and I opted for a 26 wheel instead of a 700c. I am very happy with it, but again I changed the rear tire from the normal spec, not the front tire.
The only thing I would be worried about is tire clearance on the front fork. And suitable reach on your brake arms.
switch to 20" front wheel?
Hey cazhog,
1) What is your ex-seam? How tall are you? What size frame do you currently ride? And what size crankset do you have?
2) Some (but not all) Lightning P38 unicrown-style 16/17" forks have just enough room to squeeze in a 20" ISO 406 wheel. But only with a skinny racing tire like a Continental Grand Prix or a Schwalbe Stelvio. Try borrowing a 406 wheel and putting a skinny tire on it. See if it will fit inside your fork.
If it fits, ride it, and see how you like the "feel" of the bike. Expect it to seem strange at first. But you might grow to like the change. There is a chance of crank interference with the bigger wheel. And getting your feet flat on the ground at stops may be harder. But if it fits, and you ride it, and you like it, you can put a caliper brake on the rear of the fork. Note well: even if the wheel and tire do fit, there will be no possibility of using a fatter tire and/or putting on a fender. Strictly skinnies.
3) If the wheel does not fit in your existing fork, you will need to get another fork. Lighting can sell you a very light and nice 20" one for around $200 or so: it comes in two different versions: racing or touring. Some juvenile mountain bike and BMX forks can also be made to fit, but they will be much heavier.
4) Is the change to the larger wheel worth the expense and hassle? It mostly depends on your physical stature. Shorter riders will usually be better off with the 16" wheel, while medium and taller riders will often prefer the ISO 406 20" wheel. Some people have even tried using still larger wheels. I think Ben Fox has an ISO 451 20" front wheel on one of his Lightning bikes.
If you can get your existing fork to accept the new wheel, and you can live with racing tires only, you just need to buy the wheel, tire, tube, and caliper brake. Not a big investment.
Only personal experimentation will provide a conclusive answer.
Safe riding,
Joel
My $.02: The 20" (406)
My $.02: The 20" (406) Unicrown P-38 front fork gives you minimal tire clearance. This cuts down your choices to very a very very short list. Forget about a fender. Even with a tire that fits- The Schwalbe Durano, you can not pump the tire to full pressure without it rubbing the fork crown. The maximum pressure I can use is about 85 pounds. But this doesn't seem to effect the performance of the bike. If you hit some road debris however, it is possible for the tire to pick it up and get caught in the fork crown. This happened to me on a fast descent and I was fortunate to escape with just a nasty gauge in my tire; but my skin still intact. There are alternate 20" forks which will give you better tire clearance; but they are somewhat heavier than the stock P-38 Unicrown, and may require a different front brake. Tim offered me a fork exchange; but I'm a weight weenie, and I've decided to live with the Unicrown. If you don't mind adding a few ounce -- then switch to the heavier, more user and tire friendly fork design.
20" front 26" rear configuration
I have a 20/26 P38. Though it was purchased new and I opted for a 26 wheel instead of a 700c. I am very happy with it, but again I changed the rear tire from the normal spec, not the front tire.
The only thing I would be worried about is tire clearance on the front fork. And suitable reach on your brake arms.