Rake and trail

[Leedsharlequin]

Been having this discussion with another member and although not doubting , am still somewhat confused. The issue was swapping the 19" front hoop to 17" and the need to change the stock T100 triple trees with Thrux trees. My question would be, has anyone done the swap while maintaining the stock trees? I know it can physically be done, but was curious what the effect on handling would be compared to modifying the trees. Rake and trail appear to be the determining factors to make the modification necessary. Seemed like a worthy topic.opcorn:

 

[Jhtjon]

Thought the THrux and Bonnie had the same trees

 

[Leedsharlequin]

I just learned they were different , how, I'm not sure.

Ok , looked this up..

T100 rake 28 degrees / Trail 110mm

Thrux rake 27 degrees / Trail 97mm

Both have 41mm forks. Didn't know the Thrux had 18" frt wheel.

Any takers?

 

[Leedsharlequin]

Oh well, guess I'll be the first to try:hung:

 

[1087]

Oh well, guess I'll be the first to try:hung:

You will be the first to try what?

 

[MES]

the offset is also different on the Thrux triples.

I know of no person that has gone to a 17" front with stock Bonnie triples.
Your steering geometry is going to be real funky.
I would suggest that you go with an 18" front/stock triples and stock lengh shocks.
It will really improve turn-in but not make it so unstable at high speed.
If you want it to turn in quicker still, then go with longer rear stocks. But it's going to start to get real twitchy untill you deal with the triples.

If you really want a 17" front then you would be better off getting a set of custom triples made that will accept your 1" bars and controls. converting to 7/8" is going to real expensive. -1.5* rake and decrease the offset to bring your numbers more into line.

I ride a Bonnie with Thrux wheels stock triples and stock lenght rear shocks.
the difference is quite noticeable.

Just my opinion

 

[Leedsharlequin]

Thanks for the input, greater insight already:worthy: The 1 degree difference didn't seem much, but the 13mm difference in trail did. I thought wheel size would contribute partly to this, obviously tree offset does also. I knew it would get me to the sweet shop, but not sure if my pop would be shook up when I got home.


And the 18" makes a significant difference, how about tire choice?

 

[rodburner]

I thought both bikes were the same also. The Thrux`s 1" longer shocks give it the rake and trail difference and the 18" front wheel drops the front a bit,further steepening the rake.. An 18 on the front of my bike made no difference in turn in or high speed stability.Lowering it an inch at each end hasn`t changed it much either,except for shortening the wheelbase.???

 

[Xchoppers]

Altering suspension height at either end minimally changes both rake and trail but the slight difference in handling is imperceptible for all but the most aggressive riders (racers). Reducing trail makes a bike "turn in" quicker and change direction quicker. That's why the Thruxton has a smaller front wheel and less rake and trail 'cause it's aimed at faster riders. The down side is you have to pay more attention to your line as it can quickly change if your attention should wander.

 

[localmotion411]

the offset is also different on the Thrux triples.

I know of no person that has gone to a 17" front with stock Bonnie triples.
Your steering geometry is going to be real funky.
I would suggest that you go with an 18" front/stock triples and stock lengh shocks.
It will really improve turn-in but not make it so unstable at high speed.
If you want it to turn in quicker still, then go with longer rear stocks. But it's going to start to get real twitchy untill you deal with the triples.

If you really want a 17" front then you would be better off getting a set of custom triples made that will accept your 1" bars and controls. converting to 7/8" is going to real expensive. -1.5* rake and decrease the offset to bring your numbers more into line.

I ride a Bonnie with Thrux wheels stock triples and stock lenght rear shocks.
the difference is quite noticeable.

Just my opinion

What are you using for a front fender with the smaller wheel, if any? This guy switched to the Carrozzerias with 17" rear and 18" front and has no front fender:

I want to do the same thing at some point but am not crazy about having shit flying up in my face.

 

[MES]

What are you using for a front fender with the smaller wheel, if any?

I'm using a chopped Bonnie fender that was binned by a friend 'cause I'm to damn lazy to go to the breaker a get one that looks better.

Re: Carrozzerias
I've seen 'em in person and I don't like em. We don't make enough power to need the wide rear wheel and it just slows the roll rate down. The rear is also offset(? pretty sure)
They're well made and if you like the look then go for it.
I like rodburners tri-blades better.
both are hella expensive though.

Just so you know, you can also get the Carrozzerias through TPUSA
send Carlos (1087, post #5) an E-mail. He's a helpfull guy

 

[MES]

Lowering it an inch at each end hasn`t changed it much either,.....

That makes sence as you lowered f/r equally and the geometry was unaffected.
The difference in wheelbase is mostly do to the shortend rake. The Thrux triples have -1.5* degree rake bored in. ?I believe?, (pretty sure as the headstock angle is the same)

Rod,
I find it interesting though that you didn't notice a change going to an 18".
I ride one quite twisty road quite often and the first thing I did was take it and run that road several times.
All the entry and exit points had changed and the first run was quite interesting. That whole first run just felt wrong because I was constantly out of position and the timing/shift points were different.
the 18" made the front end feel loose/light and the amount of input effort was lessened noticeably.
It took me about a month to feel like I had it down and could really press it with confidence in the twisties.

switching for 19" to an 18" is not a big deal on the freeways but when/if it get really tight it makes a difference because the exit of one corner is the entrance to the next. get one wrong and your wrong going into the next. It just keeps getting worse
nothing worse than pinnballing a run. Except crashing of course

 

[rodburner]

My rim is only 4-1/2"wide.There`s no offset.

 

[MES]

sure enough, no offset.
They're getting more appealing all the time.
When I win the lottery, I'm in.

what sizes you running?

 

[Phil-1100]

I first tried a Suzuki RGV250 17 inch front wheel in the standard yokes, the effect on handling was just what I was looking for, handling was much quicker and whole bike felt better. This was only a temperary measure as disc brake did not line up correctly and the standard Bonnie pegs hit the ground real easy.
So I had a head stem made up and fitted a Speed Triple front end.

 

[Leedsharlequin]

Being a speed triple owner I gotta tell you I love your bike, I rave about it regular:worthy: So you did put a 17" wheel on stock setup and liked it ?

 

[localmotion411]

I'm using a chopped Bonnie fender that was binned by a friend 'cause I'm to damn lazy to go to the breaker a get one that looks better.

Re: Carrozzerias
I've seen 'em in person and I don't like em. We don't make enough power to need the wide rear wheel and it just slows the roll rate down. The rear is also offset(? pretty sure)
They're well made and if you like the look then go for it.
I like rodburners tri-blades better.
both are hella expensive though.

Just so you know, you can also get the Carrozzerias through TPUSA
send Carlos (1087, post #5) an E-mail. He's a helpfull guy

I think I'm only liking just the black Carrozzerias on a Bonneville Black, which I have. Not too crazy about the other colors (although gold anodized on my bike with Ohlins reservoirs hanging off the shocks would look cool, IMO). The biggest problem I have with them as of now is that the black anodizing is going to fade, and when it does, it looks purple. If they could do a non-anodized baked enamel finish, I'd be in. The offset doesn't really bother me all that much; it is very small.

Not sure if the wider rear Carrozzeria would slow the roll rate down either. It is smaller diameter than the stock steel Bonnie wheel and much lighter in weight b/c it's made of aluminum and is tubeless. I think all-in-all, the performance gains due to lighter, smaller wheels and higher performance tires would be felt in the seat of your pants much more than all these expensive big bore and stroker kits will, dollar for dollar. I know a Bonnie will never be a crotch rocket, but to have a bike that looks as unbelieveably cool as a Bonnie and to have it perform really well is my ultimate goal. I'd never own a crotch rocket anyway, not my style.

If I ever do get the Carrozzerias, I'll probably get 'em from Carlos. He sold me my LSL clip ons, which I love. And he's such an active member of this forum and a wealth of information -- gotta support our squad!

 

[1087]

I think I'm only liking just the black Carrozzerias on a Bonneville Black, which I have. Not too crazy about the other colors (although gold anodized on my bike with Ohlins reservoirs hanging off the shocks would look cool, IMO). The biggest problem I have with them as of now is that the black anodizing is going to fade, and when it does, it looks purple.>>>

Good morning;
The black anodized Carrozzeria rims will not fade out, it features a hard anodizing finish , that 's a different process than the normal anodizing finish.
I hope this help.

 

[Phil-1100]

Being a speed triple owner I gotta tell you I love your bike, I rave about it regular:worthy: So you did put a 17" wheel on stock setup and liked it ?

It was only a temporary mock up with the RGV wheel but it convinced me it was what I wanted.
Its been on almost two years and its great but I would like to go further and jack it up, with a single shock, rising rate linkage in the rear end.
Future project me thinks. Lol

 

[Leedsharlequin]

It was only a temporary mock up with the RGV wheel but it convinced me it was what I wanted.
Its been on almost two years and its great but I would like to go further and jack it up, with a single shock, rising rate linkage in the rear end.
Future project me thinks. Lol

Were there any negative effects you can remember:chin: