Question on Pro Twin front forks

[JJ58]

One day I am going to dyno an emulated fork.

You'll be shocked... The emulators are definetly only band aids. The cartridges offer a much better feel but are a pain to adjust, unlike the emulators which can be popped out in less than 15mins and adjusted between sessions.

With the SV fork there is a hydrualic bottom out device that needs to be modified to reduce it's stiction, otherwise you'll find your forks hydrualic locked under braking.

[Robert Taylor]

You'll be shocked... The emulators are definetly only band aids. The cartridges offer a much better feel but are a pain to adjust, unlike the emulators which can be popped out in less than 15mins and adjusted between sessions.

With the SV fork there is a hydrualic bottom out device that needs to be modified to reduce it's stiction, otherwise you'll find your forks hydrualic locked under braking.

I agree with what you are saying but that is all the rules will allow to pay credence to a ''it must be as cheap as possible'' philosophy in those rules.
Moreover with all damper rod forks there is so much relatively uncontrolled rebound bleed that you have to run a ''heavy'' fork oil. That means that damper rod forks are way way more sensitive to the atmospheric temperature of the day.
If anyone wants to verify what I am saying remove a damper rod fork from your bike and bounce up and down on it on a less than 10 degree celsius day. Then warm the fork lower with a heat gun and let it heat soak for 20 minutes or more, stabilised temperature of around 20 to 25 degrees celsius ( i.e to emulate summer racing temps ). You will be shocked at the massive difference in rebound return speed. If you run cheap ''budget'' oil the difference will be more marked as there will be a much wider disparity between cold and hot flow ratings.
Emulators only sort out part of the problem with these stone age technology forks. Cheapness comes at a price, sometimes that includes crashing because the rebound speed is way too lethargic at cold temps and the team hasnt changed the oil viscosity to account for those conditions.

[FROSTY:Me]

Does this suggest then Robert that a clever pro towins guy would not only have tyre warmers but perhaps fork leg warmers too?
semi serious question


Advantage there I supose is the pretty boy racers could style their hair between races

[cowpoos]

Does this suggest then Robert that a clever pro towins guy would not only have tyre warmers but perhaps fork leg warmers too?
semi serious question


Advantage there I supose is the pretty boy racers could style their hair between races

I would imagine that with the forks would quickly drop to the ambient temp of the day or less if its wet.

[Robert Taylor]

Does this suggest then Robert that a clever pro towins guy would not only have tyre warmers but perhaps fork leg warmers too?
semi serious question


Advantage there I supose is the pretty boy racers could style their hair between races

Poos has answered the question, forks run at slightly less than ambient temperature due to being right in the cooling airstream. So the guys that are serious would change oil viscosity for the conditions.

It does though make sense to have a shock warmer

[GSVR]

Don't hydraulic systems warm up when they are doing work like absorbing shock loads? What happends to all the energy thats absorbed?

Some guy on here was saying his standard rear shock got so hot he couldn't touch it. Why are the front forks any different?

[FROSTY:Me]

Don't hydraulic systems warm up when they are doing work like absorbing shock loads? What happends to all the energy thats absorbed?

Some guy on here was saying his standard rear shock got so hot he couldn't touch it. Why are the front forks any different?

My thinkin exactly --kinda like tyre warmers--the work of goin upn down would keep the legs warm.
Holey shit---I can see it now. Mr speedracer 123 is up due for his first race of his career. His ever vigulent crew wait thill the last moment before removing tyre warmers,front shock warmers,rear shock warmers and patented seat warmer.
With a full grid of 35 bikes the national grid heaves a sigh of releif as all this gear is turned off.

[cowpoos]

Don't hydraulic systems warm up when they are doing work like absorbing shock loads? What happends to all the energy thats absorbed?

Some guy on here was saying his standard rear shock got so hot he couldn't touch it. Why are the front forks any different?

forks run at slightly less than ambient temperature due to being right in the cooling airstream.

It does though make sense to have a shock warmer

and the rear shock is out of the airstream and is also warmed by engine heat aswell.

[GSVR]

I'm thinking heated handgrips might be a better investment for the winter series. 10 mins waiting on the dummy grid and everything is stone cold anyway.

[Robert Taylor]

and the rear shock is out of the airstream and is also warmed by engine heat aswell.

And there is so much mass of metal to absorb heat as well. We have tested this sometime ago.

[cowpoos]

I'm thinking heated handgrips might be a better investment for the winter series. 10 mins waiting on the dummy grid and everything is stone cold anyway.

lol good call gary!! heated hand grips and a hotwater bottle!!

there should still be plenty of heat left in tyres,etc after 10mins waiting on the dummy grid...the surface of the tyres may be cold..but the carcuss and rim should and would have heat still in it.

[GSVR]

and the rear shock is out of the airstream and is also warmed by engine heat aswell.

Yeah that rear shock on the SV must really be a hard on to get right in winter with the exhaust and engine heat. Its temp range must be huge compared to the front. Rear shock heater would be a necessity to get it even close to working right.

[Pussy]

Even in a road bike set up, we ended up getting RT to put lighter weight oil in the forks of Gassit girl's K1 SV650 for the winter months. The rebound was too lethargic otherwise. For some reason the K5 SV650 was able to run the same weight oil year round

[Robert Taylor]

And there is so much mass of metal to absorb heat as well. We have tested this sometime ago.

I also hasten to add that there is approximately 5 - 6 times the volume of oil across two forks compared to a typical rear shock, so there is a massive amount more oil to heat. Allied to that each fork leg has approximately only 15 - 20% of the damping force of a typical rear shock at kerb strike velocity. Less damping equals much less heat build up

[Robert Taylor]

Even in a road bike set up, we ended up getting RT to put lighter weight oil in the forks of Gassit girl's K1 SV650 for the winter months. The rebound was too lethargic otherwise. For some reason the K5 SV650 was able to run the same weight oil year round

There in fact would still have been variance, just less obvious. And this was because of precision remachining on the damper rods to actually get them to sit on the same centreline as the fork tubes! Thereby giving less bypass, but this adds to the cost, inevitably.