front wheel

[dfh]

Been wonderin'

Has anybody got the weight of a TRX front wheel sans tyre & discs?

Why ?

Well I remember pulling the front wheel out of my mates SV650 a couple of years ago and being surprised at how much lighter it was compared to the TRX wheel. The other noticeable difference was how much better the front end felt over rough surfaces ( the kind of surface scabs we find on suburban streets in OZ). Now before we go off on a tangent with comparative suspension quality both bikes have correctly specified and installed Eibach springs and Race-tech gold valve emulators ( I installed said bits in both bikes), the forks are both 41mm and they have the same size and type of tyre, but it is interesting that even thought the SV is 25-30kg lighter than the TRX it rides better and the only answer i can come up with is unsprung weight.

So has anyone got any comparative data on front wheel weights?

DFH

[Tarwetijger]

Not from the TRX, but I do have some numbers of the YZF:
Original rims with Pilot Power tyres, including discs
Front 12,4 kg
Rear 13,9 kg

Marvic magnesium rims with front metzeler racetec and rear supercorsa,
including discs (front fitted with ABM Peak wave discs, which are also lighter)
Front 9,8 kg
Rear 11,5
Sprocket carrier (including sprocket): 2,3 vs. 1,3 kg

So, just for the idea.

[slow codger]

Rider position, weight distribution over the front wheel, wheel base, steering head angle ? .Lot of factors to look at not just unsprung weight.

Dave E

[dfh]

Rider position, weight distribution over the front wheel, wheel base, steering head angle ? .Lot of factors to look at not just unsprung weight.

Dave E

Only talking about ride quality in a straight line, so those factors will have little effect. In fact the wheelbase and head angle should work in the TRX's favour.

DFH

[LozLul]

dfh,

Just a quick question to bring us little further from the original subject:

You mentioned that you've installed a race tech gold valves to TRX. I take it that you did the brazing work yourself as well. Did you shut all five holes on the larger diameter part of damper rod leaving only one hole a bit lower for rebound? Or did you enlargen this lower rebound hole/drill a new one to match the original rebound charasteristics of your forks with preferred rebound settings? Or better still, taken that you seem to have quite some knowledge on suspension, and a lot of feel regarding the ride to boot, did you come up with something original en route to get the best out of the TRX's front end...

Thanks for your input!

[dfh]

dfh,

Just a quick question to bring us little further from the original subject:

You mentioned that you've installed a race tech gold valves to TRX. I take it that you did the brazing work yourself as well. Did you shut all five holes on the larger diameter part of damper rod leaving only one hole a bit lower for rebound? Or did you enlargen this lower rebound hole/drill a new one to match the original rebound charasteristics of your forks with preferred rebound settings? Or better still, taken that you seem to have quite some knowledge on suspension, and a lot of feel regarding the ride to boot, did you come up with something original en route to get the best out of the TRX's front end...

Thanks for your input!

Tried to go to Finland once... caught a boat from Stockholm that was very cheap price. Boat sailed into the Baltic and all the other 500 (grey haired) passengers headed to the bar. As the boat neared Helsinki it turned around and sailed back to Stockholm. Why? I had caught a special drinking boat that sold cheap booze as soon as the boat left Swedish waters and none of the passengers had no plans to go anywhere except the bar

I did make it to Finland eventually... by motorbike. Nice place. Riding on snow is like riding on the best of dirt roads.

As for the forks... when you pull the damper rod out, as you have to to drill out the compression damping holes as per the instructions, you will see that the rebound adjuster is a rotating "plug" in the top of the rod. This plug is held in place by a circlip from memory, and it has three little holes in it. Pull this out and discard ( I use one of them as a paperweight on my desk) Now the Race-Tech instructions ask you to braze up the holes in the larger diameter part of the rod but what the Race-Tech expert in Sydney did was as to "borrow" my other plug supply a piece of tube to replace it that was an interference fit ( tap it in with a hammer... ) in the top of the rod . As long as the tube covers the holes in the top of the rod and is not too thick walled as to stop the emulator sitting properly at the top of the rod its job done. The rebound hole just under the larger part of the damper rod is all you need.

Worried about rebound adjustment? Don't be. Unlike compression side of things where vertical acceleration of the wheel is defined by the shape and size of the bump, hence the need for the emulator, rebound is a factor of spring rate and vehicle weight. So the fork has a small difference between maximum and minimum shaft velocities in rebound. Race-tech recommend 10wt fork oil, I use 15wt wirh either the .9kgmm or .95kgmm forksprings fitted.

I assume that you are replacing the springs to match your weight, if you are already using upgraded springs what oil and rebound adjuster settings are you using on the fork?

DFH

[LozLul]

dfh,

It must've been quite frustrating experience to be stuck on that boat - especially if you didn't fancy the popular entertainment involved. You see, alcohol-taxation-wise we support one of the most paternalistic regimes known to man. This is especially true in Finland, but to some degree in other Scandinavian countries as well. Simply jumping on a boat that takes you just out side the legislation is a convenient way to drink cheap. Additional benefits include that chicks (should there be any under the tender age of 60) cannot escape or leave early when, of course, the "Motel room" factor of the cabins comes quite handy etc. That's all there is to it. Other wise it's just boring, plus you don't actually get anywhere.

What is this a motorbike forum? OK, allright...the snug fitted piece of tubing covering the top holes actually sound quite interesting. Especially as my brazing skills are non-existent. I have to look into that.

You made a fair point on the charateristics of the rebound damping. However, I feel that there is some mediation to be found between oil weight, rebound hole diameter (or volume) and the quality of ride. For example, by shutting all of the holes on the larger diameter portion of damper rod you effectively induce similar rebound damping as in original forks with rebound damping set to max (if the spring rate and oil weight stays the same). As I preferred the to set the original forks to "2", which means there is an additional hole with a diameter of 1,7mm, there might be a difference of some significance to be found. But then, I have to take into account that I'm changing the springs (as you assumed) to the Race Tech ones with .9kgmm. Furthermore, I'm also likely to change oil weight from 12,5 (a bit heavier to reduce excessive diving) to a bit lighter (maybe 7,5-10). This, of course, affects rebound damping...

So complicated, and therefore, exciting!

[dfh]

dfh,
So complicated, and therefore, exciting!

Much better than a Baltic cruise..... DFH