748 superbike front end on old M750

[junior varsity]

that's not what he means by tank-slapper.

you just have to get used to your setup, you may like the way it steers for your riding style.   I would suggest a steering damper as well.

[motolady]

that's not what he means by tank-slapper.

you just have to get used to your setup, you may like the way it steers for your riding style.   I would suggest a steering damper as well.

hence the winky face... i know he means the actual action of the bars slappin and whackin back and forth in a loss of control.

i'm looking into the steering damper while I'm doing my frame chop and powdercoating. thanks for the feedback!

[junior varsity]

no prob.   as you may surmise, I dig modifying the bikes quite a bit.

[Raux]

a good tank slapper will tear apart your steering head, literally ripped the metal on mine, like a toilet paper roll being ripped open, from the steering stops being hit so hard.

[corey]

okay okay.. so i know i'm no expert on this stuff, and by no means will claim to be one.
i've dropped 999 forks into my S2R with great results using stock triples with typical monster offset of 25mm...

but what i'm thinking, and correct me if I'm wrong please, is that the 36mm offset will do exactly the OPPOSITE of making the bike more twitchy... technically the wheelbase has just been extended by what, 11mm because it's an older 750 with originally a 20mm offset? now doesn't a longer wheelbase typically mean MORE stability in straight-line tracking, and SLOWER turn-in?

i do understand that now the weight ratio of what is over the front wheel is a bit lower, but with the obvious addition of clip-ons, that should negate that effect... (while also making this bike ridiculously far-stretched when it comes to riding position)...

i'm not knocking her approach, i'm just genuinely curious on what the ACTUAL effects on geometry and mechanics are...

thoughts?

[corey]

I'd like to add a steering damper.

It's not even possible for my bars to hit my tank at the angle of the 748 clip ons. 

Also, and excuse the double post...
I know it's not possible for your bars to hit your tank, which is no doubt a result of the extra offset from the 748 triples... but if that's the case, and considering you completely removed your steering stops from the stem tube of your frame... what this SHOULD mean is that if you WERE to enter a "lock-to-lock" "tank-slapper"... your forks would be bashing against your actual frame?

I mean, with no steering stops, if you crank that sucker either way and keep going, eventually SOMETHING is going to make contact somewhere. what is it? is it safe?

[junior varsity]

No no!

First your S2R and all Monsters 2002+ are 30mm offset from factory!  Pre-2001 Monsters have the 25mm offset. The Ducati SBK's come with 36mm, but feature adjustable steering angle & many, if not most, Ducati racers are running aftermarket triples with a lower offset (or adjustable triples, like AMS, Attack Performance, or IMA Special Parts)

Second, it is not the extension in wheel base here that is significant (adding to swingarm has a much more pronounced effect than anywhere else, hence why Ducati has been trying to move engine forward), the significant change is to trail #!  I will ask Jason to post a better explanation, he's got a better understanding than I do.

[stopintime]

Increase offset to decrease trail = better turn in, but less stablity.

From Motorcycle Consumer News

[junior varsity]

Yes, and changes to rear ride height and fork-in-triples height will effect your geometry as well. (it alters several variables related to length of one side of the front end triangles, the wheel base, and the effective steering angle)

[junior varsity]

The converse of the above statement would be: "decrease offset for more stability (especially when leaned over, I'd say), but require more effort in your steering inputs."

Big offset: dives/darts into corners very quickly, but will feel twitchy or uneasy when you're in a sweeper.

Small offset: push more to make it turn, but feels more stable, especially on driving out of the corner.

[junior varsity]

I've seen a nifty spreadsheet that is Duc-specific for geometry stuff, I will have to see if I can find it or if it's "private goods". It had pull-down tabs and the various default OEM measurements - providing a glimpse into how any one change might affect others. Maybe the IMA folks here or in Torino will have a similar type document, or I could try to make one me self

[motolady]

Also, and excuse the double post...
I know it's not possible for your bars to hit your tank, which is no doubt a result of the extra offset from the 748 triples... but if that's the case, and considering you completely removed your steering stops from the stem tube of your frame... what this SHOULD mean is that if you WERE to enter a "lock-to-lock" "tank-slapper"... your forks would be bashing against your actual frame?

I mean, with no steering stops, if you crank that sucker either way and keep going, eventually SOMETHING is going to make contact somewhere. what is it? is it safe?

To answer your question, I'm replacing the steering stops. I have someone working on frame chop/steering stops as we speak.

I've seen a nifty spreadsheet that is Duc-specific for geometry stuff, I will have to see if I can find it or if it's "private goods". It had pull-down tabs and the various default OEM measurements - providing a glimpse into how any one change might affect others. Maybe the IMA folks here or in Torino will have a similar type document, or I could try to make one me self

I would love to see this!

[corey]

To answer your question, I'm replacing the steering stops. I have someone working on frame chop/steering stops as we speak.

we don't like to see anyone getting hurt around here.