What do you guys think of this tripod joint angle

[Bemo]

Our 07 car had quite a poor tripod angle, but still much better than this. Back then we had a "tripod graveyard" in our shop. If you manage to do some hundreds of testing kilometers you should order some tripods in advance...

Btw, happy birthday Pat!

[Xeilos]

The driveline inefficiency alone should be enough to make you cautious at angles above the 12 degrees.

Driveline manufactures may say you can use up to "angle X" but that is for non-extended length, low speed use.

From everything we have read as a team, anything above 11-12 degrees results in significant losses (think efficiency jumping off a cliff). We are going to be evaluating this in the next two months as we are have been running 11 and 16 degree driveshaft angles for years without real validation.

Also, we have had wear problems at 16 degrees though the root cause is up for some debate and/or speculation.

[Rex Chan]

Dear Pat Clark,

For those who don't have as much knowledge/experience, could you tell me if these are the other design errors you speak of?

1. Load path for the pull-rod>bell crank activation>damper is at too much angle

2. Camber change through spherical bearing rod ends, which puts a-arms into bending.

3. Too narrow a base for tie rod

4. Reaction force of damper is not reacted well into the chassis (force from bell crank goes up, but bracket is the wrong way - will shear/bend rather than be in tension/compression)

BTW, I'm an engine guy, so don't spend long looking/understanding suspension loads.

[coastertrav]

Rex,

The rod ends do not appear to be in bending as the forces from the A-Arms are co-linear with the rod end itself.

The toe base looks way too short, I've always thought you want it as large as you can fit in the wheel.

The load path through the suspension rocker looks miserable, and I hadn't noticed the shock mount till you said something, but that's definitely not how I would have done it.

But hey, I'm just the electronics guy.

[Spetsnazos]

Hey guys I forgot to put on my flame suit...not fair.

[wagemd]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xeilos:
The driveline inefficiency alone should be enough to make you cautious at angles above the 12 degrees.

Driveline manufactures may say you can use up to "angle X" but that is for non-extended length, low speed use.

From everything we have read as a team, anything above 11-12 degrees results in significant losses (think efficiency jumping off a cliff). We are going to be evaluating this in the next two months as we are have been running 11 and 16 degree driveshaft angles for years without real validation.

Also, we have had wear problems at 16 degrees though the root cause is up for some debate and/or speculation. </div></BLOCKQUOTE>

We have run up to ~8-9 degrees a few different years with acceptable results, though a few years back, one of the cars did have a nasty habit of ejecting halfshafts under load which was always entertaining...

I believe Taylor publishes a chart of efficiency loss vs angle? Then you can choose/limit/discover your driveline losses (though it wont tell you much quantitatively about reliability, you'll just have to test that)

Since its already designed and built, you might be able to get away with classifying it as a wear item, inspecting, and replacing regularly, depending on if testing indicates it could be a problem.

[Spetsnazos]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by wagemd:
[QUOTE]Originally posted by Xeilos:

I believe Taylor publishes a chart of efficiency loss vs angle? Then you can choose/limit/discover your driveline losses (though it wont tell you much quantitatively about reliability, you'll just have to test that)
. </div></BLOCKQUOTE>

Never seen that chart, do you have a link to it?

[PatClarke]

Quote Spetsnazos "Hey guys I forgot to put on my flame suit...not fair".

Sorry mate, but you posted the picture asking for comment. You have not been flamed, the comments have been critical about a fairly 'ordinary' design.

Most (but not all) of the shortcomings have been identified here. Unknownst to anyone here, there has been some back channel discussion between Design Judges about the picture and the feelings are mutual. (Oh, you didn't know that the experienced Judges maintain contact and discuss this stuff?? Darn, now I have let the cat out of the bag!)

So don't feel miffed, no-one (least of all me)is flaming you. Feel free to PM me if you feel aggrieved.

Cheers

Pat

[Spetsnazos]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PatClarke:
Quote Spetsnazos "Hey guys I forgot to put on my flame suit...not fair".

Sorry mate, but you posted the picture asking for comment. You have not been flamed, the comments have been critical about a fairly 'ordinary' design.

Most (but not all) of the shortcomings have been identified here. Unknownst to anyone here, there has been some back channel discussion between Design Judges about the picture and the feelings are mutual. (Oh, you didn't know that the experienced Judges maintain contact and discuss this stuff?? Darn, now I have let the cat out of the bag!)

So don't feel miffed, no-one (least of all me)is flaming you. Feel free to PM me if you feel aggrieved.

Cheers

Pat </div></BLOCKQUOTE>

Oh I understand people are trying to help and I'm not upset or surprised. I wasn't part of the suspension design(was engine/drivetrain/sprockets/chain) but I will note what people are saying and pass it on to the other guys who were. I seriously didn't think the axle thing would be an issue because all the research I could find said it would be fine up to 20 degrees.

I knew there would be drivelosses associated with a huge angle but I didn't think it would be huge up to 20 degrees. Live and learn

[Rex Chan]

coastertrav: sorry, when I said bending, I meant that if the threaded part of the rod end was made shorter/longer, due to the constrained ends, it will put the a-arm in bending in plane with the arms.In the extreme, if you could extend the rod ends by 1", then they should end up much further apart from each other. However, the brackets constrain the ends to be always a fixed distance apart.