Stock Ride Hight and Steering Head Angle Vrs. Ideal?

[BigGuy]

Hi all, I know this is minefield of questions but here it goes. Among many things I'm in the process of fitting an R6 swing arm to my newly acquired RZV frame. I have it all set up on a flat, level and square steel table. My first question is what would be the stock steering head angel and what would be the ideal angle for street use? Also in the stock set up are the lower frame tubes supposed to be square (parallel) to the world? My last question would be does anyone know the from the ground to the center of the hole for the swing arm pivot bolt size? Obviously I'm not a fabricator of motorcycle frames but I am a Toolmaker by trade and my family owns a machine shop so I feel I'm not completely without the ability to do this.

Thanks in advance.

[rd84]

I wonder if it would be best to measure something modern like an R6 or CBR600RR <ahem > and set your bike up with similar wheelbase CofG height and position and same headstock angle ? - Ive got an RZV500 project with a 2CO R6 swingarm - however its away at NK Racing so I can't take any measurements for you. I'll also be interested in the answer to your question. I weighed my standard RD500 and it has a unladen 55%/45% - Rear/Front weight bias - which is the opposite of modern thinking which seems to be from 50/50 to maybe 52% front ?

Best of luck with your project.

Cheers
Paul

[steveho]

My 3MA YZR rep has 52-53% front bias. Not by choice, but it is what it is.
Just for info.

[BigGuy]

Thanks for the replys guys. It would be nice if some of the guys who have made successful suspension modifications could share some final steering head angle, rake and ride height specs? I know this is hard won information.

[RGVSTEVE]

BigGuy,

I sent you a PM, I might be able to help with some of the info your looking for.

Steve

[Blobber]

When stock my RZV had a front weight bias and felt proper old school to ride. Now with FZR1000 forks/wheel, YZF600 rear wheel adjustable length Nitron shock and shock mount brackets modified for approx 25mm rear lift the bikes ride and handling is transformed.

The weight bias is now slightly to the front I think 52 vs. 48 when I had it MOT'd.

The forks are sticking through the yokes by approx. an inch.

Bike now handles more like a modern bike and definitely no head shaking. I just need to change the fork oil to something heavier and I will be very satisfied with my modifications for road use. Was also thinking of converting the forks to a cartridge type or possibly new progressive springs.

If you need any dimensions from me let me know.

[adr1an]

Hi Big Guy,
I have the standard steel frame with a 2007 R6 swingarm and 2005 R1 forks. I have an standard RZ500 ohlins rear shock with 160Nm spring and a rideheight adjuster.
The standard RZ500 set up is 1375mm wheel centres, 26 deg rake and 95mm trail.
My thoughts were to look at a 2005 R1 geometry (as I have one) as a baseline target and go from there.
A 2005 R1 set up is 1395mm wheel centres, 24 deg rake and 97mm trail.
With my modified RZ500 I have now achieved 1420mm wheel centres, 23.75 deg rake and 93mm trail.
I have used the rear shock ride height adjuster and dropped the front end to find what was an optimum for me, so it's in the region of the data above.
Handling is much better than stock as you would expect, suspension very much better and in general much like a modern day sportsbike. It looks right as well, for what's that worth and the ground clearance is good.
Hope this helps. Let me know if you need more.

[BigGuy]

Hi Big Guy,
I have the standard steel frame with a 2007 R6 swingarm and 2005 R1 forks. I have an standard RZ500 ohlins rear shock with 160Nm spring and a rideheight adjuster.
The standard RZ500 set up is 1375mm wheel centres, 26 deg rake and 95mm trail.
My thoughts were to look at a 2005 R1 geometry (as I have one) as a baseline target and go from there.
A 2005 R1 set up is 1395mm wheel centres, 24 deg rake and 97mm trail.
With my modified RZ500 I have now achieved 1420mm wheel centres, 23.75 deg rake and 93mm trail.
I have used the rear shock ride height adjuster and dropped the front end to find what was an optimum for me, so it's in the region of the data above.
Handling is much better than stock as you would expect, suspension very much better and in general much like a modern day sportsbike. It looks right as well, for what's that worth and the ground clearance is good.
Hope this helps. Let me know if you need more.

Thanks for the detailed reply's guys! Good info, just the kind stuff I was hoping to see. Forgive for asking but I was under the impression that if there was less than 24 Deg head shake would be an issue?- Obviously it is working for you so that must not be true?

[adr1an]

Most modern sports bikes will be in the 24deg rake angle region. I'm not sure that + or minus 1 deg will make that much difference as there's a lot of other contributing factors, wheelbase, trail, weight distribution, suspension, wheel size, tyres, 30 year old frame, rider ability (big influence).

It's a 30 year old bike, immaterial of what we dress it up with, forks, swingarm, wheels etc etc, so if we get closeish and it feels ok, I think that's as good as can be expected.

Sorry, mean't to add, no head shake to mention. Having had a standard RZ also, I'd put that in the main down to the 16" front and tyre profile. Then again, because it made you slow down that was a bonus, as the brakes were pretty average.

[RuZty]

A big factor affecting trail is fork offset, newer forks have less, allowing a decent amount of trail at steeper rake angles. I used to work with a guy who choppered a metric cruiser, used fork extenders and aftermarket triple clamps to kick the front wheel out. He couldn't understand why the thing shook like a dog shitting razor blades at speed, it took me ages to convince him that he had taken the trail past zero and the last place his front tire wanted to be was pointing straight ahead.