shawnh

Did you know Pit Shimizu have an ideal insert for 60d tyres which is one piece and therefore doesn't need glueing.
Their part number is PS0458

Granpa

Nope. Good to know.

KA2AEV

iTrader: (1)

Are they readily available? Never heard of that!

Granpa

Upon reflection, since the firmness etc. is an unknown quantity here, I can't say whether this is a good thing or not. The Tamiya insert is a good combination with the PS tires for the track surface and layout my Mini sees. The PS insert may be better or worse. I don't know.

Please note that I use PS tires for practice, car set up, and because their cost is lower and they are more durable. They are also 0.2 to 0.3 seconds quicker than the old S-Grips and nearly a full second faster than the new S-Grips. I don't race with them cause they are illegal for TCS races. For open tire Mini races, 55D tires are probably a better choice.

Also, no offense intended here, but just can't support your statement that these are an ideal insert for 60D tires. They may be, but I'll leave it to others to try and post their experience.

Granpa

Please let me amend my post cause it was, even being charitable, pure crap the way it was worded. It should have said that zero rebound is a good goal, not a default position. Rebounds of much more than 2mm is counterproductive in most conditions, but can be useful in some situations. Must be more careful in the future.

Jim's comment was very astute. It's nearly impossible to build a zero rebound shock using normal methods with TRF shocks when all their components are in good condition. When placing the top of the shock back on, you will have some air trapped inside the cap that cannot escape past the bladder or thru the cap even before the cap is fully tightened. As you fully tighten the cap, this air will be compressed which will cause the bladder to deflect and the shock shaft will be extruded. Thus a small amount of rebound and not a true zero rebound shock.

If someone has a procedure to build a true zero rebound shock without modifying the cap, please post it. I know I'd be very interested. And yes, I do know that you can drill a small hole in the cap to bleed out the air.

monkeyracing

iTrader: (10)

Have a large container of silicone oil and build/cap the shocks beneath the surface of the liquid? That's about the only way to get them absolutely, positively filled. Terribly impractical and messy though.

There's a great two part video on YouTube covering this subject. It's about as close as you'll get and is probably what Granpa does when assembling his. Vids are Japanese, with English subtitles.

+ YouTube Video

+ YouTube Video

marcos graveyar

Will drilling a hole in the plastic part of the cap help eliminate any excess air that there would be in there ?

niznai

Yes.

I have seen the hole drilled exactly through the ball end of the shock cap, so it is blocked (well, as good as the ball can block it) when the shock is on the car.

Not sure if the method works if you use the little foam discs inside the cap.

iti20090

Our local guys are re-inventing the wheel by trying 21T and 17T and now evolving to the 13T brushless for M-Chassis.

I favour going straight to the Aussie rules brushless current rule. Some reading suggests the control brushless motors was the HOBBYWING EZRun Combo B1 35A V2 ESC+13T/3000Kv brushless motor, especially as it was specifically engraved for that racing.

Is this still to case and where might I be able to download a copy of the specific Aussie brushless motor rule?

Thanks and regards
Dave

Sith Lord

iTrader: (21)

There's not a lot to the rules. These Vortec Rules http://www.vortec.org.au/v/Electric_...ass_Rules.html are the general ones adopted by most states and clubs. 'Rebranded' systems also allow the use of Yeah Racing and Venom branded Motor/ESC combos which are the same product essentially, just a different colour.

It works here. We don't see any Motor/Speed issues, arguments between racers, etc. Just comes down to set up and driver skill.

sosidge

You've got (potentially) three things acting as an additional spring in the cap of the shock.

- The bladder. Naturally it wants to return to it's shape. You can't do anything about that (maybe a softer one but I don't know of any on the market for the Tamiya shocks)
- The foam wedge. You can take it out. I personally have never run them.
- The air pocket. Wants to stay at it's original volume. You can drill the cap to open it to the atmosphere. Drilling where the ball is doesn't make sense, I have some drilled caps that use a ~1.5mm hole through the top at an angle.

Having made some measurements I don't think that drilling the caps makes any worthwhile difference to the shock. The decrease in effective spring tension is much less than the difference between two standard spring rates. You'll notice that any rebound measurement you choose will be completely different after 5 minutes anyway. Just build the shock consistently, I follow the instructions to the letter with the exception of the foam wedge.

Granpa

Jim, great videos and I do pretty much build shocks this way. Perhaps not as neatly cause oil usually winds up all over the shocks, my hands and the table. Having a little oil come out over the top threads is no big deal and helps keep air from leaking in under the bladder. The oil also makes unthreading the top cap easier when you rebuild the shock. Those fine threads and time can make the cap very difficult to remove if assembled dry. Besides a little motor spray cleans it off.

There are some differences tho. I do not use 4mm of spacers between the short coupler and the shock body. I push the coupler up until it touches the shock body , then finish the assembly without anything on top of the bladder. This usually gives you c 1-2 mm of distance between the shock body and the coupler.Using 4mm of spacers will give you at least 4mm of rebound. This could lead to a discussion on rebound and how it affects Minis and when and how to use it. Let's just say sometimes it's good and sometimes it's bad. If you think weight transfer is difficult to explain, this is even harder.

Someone posted that after 5 min. any rebound measurement will be completely different. My experience has been completely different in that my shocks usually don't change and are rebuilt when they do. Most go months and a hundred or more runs. If what he posted were true, shocks would have to be rebuilt after every heat. Let's just chalk this one up to a careless post. We all screw up once in a while.

I never said that drilling a hole in the cap was a good idea cause I'm just not sure. It is the only way that I know that will give you a true zero rebound shock. The hole is drilled in the plastic piece and should be about 1mm. A #60 would be about right. If anyone knows how to build one w/out drilling the cap, I'd sure like to know.

back9monsta

iTrader: (18)

http://www.tqrcracing.com/forum/gall...=20&doc_no=173

Just wanted share a video from a local TCS carpet race from a couple weeks ago.

shawnh

You may need to search for 'PS-0458' but they are available.
I've only come across them within the last 12 months and they certainly save the time and effort (yes, I'm lazy) of gluing the ends of the Tamiya inserts together.

No offence taken. Just replace the word ideal with; a very suitable alternative

To be honest though they are both of a very similar firmness and a mere mortal like myself is very hard pushed to notice a difference on track.
For me they are much more user friendly and eliminate the inconsistencies of the Tamiya insert, which as we know has a mind of it's own if not fitted correctly.

MD

iTrader: (136)

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