COFSTA

For street riding and sport touring, is there a significant difference in the feel and cornering ability of a bike with a 19" front wheel as opposed to a 17"?


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All things being equal - if I understand rake / trial / offset correctly - increase in the diameter of the front tire would increase your trial. This would help the bike turn quicker in the corner esp at the apex. But a bike with a shorter wheelbase with equal size tires would have the same effect. The problem is as your trial increases at some point you loose high speed stability. That's why MXers have 21" front tires and spoke bikes have 17' tires.

Well I'm not talking about track days, just spirited riding. I've been contemplating if I really would miss the 17" wheel like in my Tiger if I had a bike with a 19" wheel like a Stelvio, R1200GS, Super T, etc...


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PirateRiderBen wrote:Well I'm not talking about track days, just spirited riding. I've been contemplating if I really would miss the 17" wheel like in my Tiger if I had a bike with a 19" wheel like a Stelvio, R1200GS, Super T, etc... Sent from my iPhone using Tapatalk

It depends on what you mean by "spirited". Doesn't seem to bother me or Brick. Of course I have no idea how my GS would handle with a 17" front.

Marc K wrote:All things being equal - if I understand rake / trial / offset correctly - increase in the diameter of the front tire would increase your trial. This would help the bike turn quicker in the corner esp at the apex. But a bike with a shorter wheelbase with equal size tires would have the same effect. The problem is as your trial increases at some point you loose high speed stability. That's why MXers have 21" front tires and spoke bikes have 17' tires.

But--it seems like it would also increase the rake angle by raising the front end, thus slowing down the turn-in. Or am I all wet.

I guess the only logical answer here is to go ride one of these 19" monsters.


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PirateRiderBen wrote:I guess the only logical answer here is to go ride one of these 19" monsters.


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beemerbob wrote:

Marc K wrote:All things being equal - if I understand rake / trial / offset correctly - increase in the diameter of the front tire would increase your trial. This would help the bike turn quicker in the corner esp at the apex. But a bike with a shorter wheelbase with equal size tires would have the same effect. The problem is as your trial increases at some point you loose high speed stability. That's why MXers have 21" front tires and spoke bikes have 17' tires.

But--it seems like it would also increase the rake angle by raising the front end, thus slowing down the turn-in. Or am I all wet.

No that's true - to keep the turn effect you must lower the forks in the triple tree to keep the height of the headstock down.. Dirt bikes get around this by have a tight rake angle at the headstock, but if you notice they sit tall in the front. It's all engineering - take a little here - add a little there - to balance the wanted effect. MotoGP bikes have a long wheel base to counter the HP lift effect - and have a tight trail / rake angle to help them turn. "SCIENCE !" as my wife would say ! All this math is making my head hurt - time for a beer.

Did someone say beer?


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