Revo Adaption

[Pari]

Hi, I've thinking a lot recently about how to get the Revo's lighter and still retain the feel of them. I love my Revos, so this is a little something I put together this weekend.

I just hope I can load the images ok, cause I always seem to have trouble.

I probably need to check the dimensions a little but if any body was keen to make these up and try them out the CNC is pretty simple and I could mail the 3D.

I've made the base plate so it would bolt straight into a normal skate truck hole setup, unlike original Revos that you have to drill a special hole configuration.

[bakersdozen]

Looking good Pari will be watching this thread with interest! Good luck and let me know when I can order a set

[m.klinge]

Hi, I've thinking a lot recently about how to get the Revo's lighter and still retain the feel of them. I love my Revos, so this is a little something I put together this weekend.

I just hope I can load the images ok, cause I always seem to have trouble.

I probably need to check the dimensions a little but if any body was keen to make these up and try them out the CNC is pretty simple and I could mail the 3D.

I've made the base plate so it would bolt straight into a normal skate truck hole setup, unlike original Revos that you have to drill a special hole configuration.

I would love to get my hands on your drawings - now sure if I can get them machined, but I will certainly give it a try :-)

//M

[Pari]

I would love to get my hands on your drawings - now sure if I can get them machined, but I will certainly give it a try :-)

//M

Just let me check over the dimensions when I get some time, and I'll PM them to you. Might take a few days as I've got a lot on.

[m.klinge]

Just let me check over the dimensions when I get some time, and I'll PM them to you. Might take a few days as I've got a lot on.

Cool thanks a lot, I'm leaving for Egypt this morning so no rushing it ;-)

//M

[plummet]

the single biggest weight saving will be changing the axles to titanium.... not a cheap weight savings by any means... but the most significant.

[Pari]

Yes , I think my Revo axles are titanium. Last week I got a quote from a prototyping company in China for a pair of Titanium axles and they wanted $300. That was for a 9.5mm, I'd hate to think what a 16mm bar would cost!

[SoutherlyBuster]

I'm guessing a lot of the cost is associated with machining Titanium, you need specialist machines to do it.

[Pari]

I guess so, I don't really know. But it's pretty tough. I'm gonna try some one else and get a second opinion.

[airjunkie]

First of al those truck design look awesome - nice work

as for the price of the titanium

. . . . the first set of titanium axles i got came from spike at Design Extreme when he was still manufacturing them and cost me 150 pounds

i purchased a second set from a friend for one of my other decks for 50 pounds which was about the cost of the raw materials

titanium is a very soft alloy ( the nylon in the revos does flat spot the axles a bit it over time )

it is very easy to machine the problem arises when you want to weld it this has to be done in a zero oxygen environment (argon i think from memory but not sure)

one of my good friends was lucky enough to have some made (as a gift ) out of some really exotic titanium (as its an alloy there is many variations and prices) How they got around the welding was to machine a very shallow groove in the middle of the axle enabling them to use two stainless steel half rings and weld them to each other with the groove keeping it in place

Titanium is actually slightly less strong than stainless steel so don't skimp on the axle thickness. . .

i have a few different revo setups and three different styles of axle in stainless and Ti if anyone wants any pictures or dimensions i am happy to help

[Pari]

Titanium is actually slightly less strong than stainless steel so don't skimp on the axle thickness. . .

i have a few different revo setups and three different styles of axle in stainless and Ti if anyone wants any pictures or dimensions i am happy to help

Hi, apologies for not replying sooner, v busy. I'd love to see some pics as it might trigger some more ideas for the perfect truck if there is such a thing.

I been thinking about you info and comments on using titanium and the problems of welding and cost etc.

I think I might have come up with a solution that is cheap, doesn't require welding (not titanium at least) and should be light and super strong.

I sourced a Carbon Fiber tube that has a 12mm ID and 16mm OD that is true Odegree weave. (weave running the length of the tube, so still and strong).

How about a 12mm steel axle with the washer welded in the middle like the normal revo truck, then it is sheaved on either side with the CF tube, it could be epoxied in place, or not as it will be held together once the wheels go on. I'm not an engineer so i might have missed something, but it would solve some major problems.

Here are some images.

Oh and I updated the geometry from the previous render as I had some sizes out. This is more true to a finished product now.

[Guster]

Unfortunately that makes a weak spot in the middle of the axle where the axle will fold. I'd suggest making the carbon continuous and gluing a retainer in the middle. Its' only purpose is to prevent the axle shifting if it is bumped from the side.

CKB has been doing this with carbon sleeved stainless. They also tried elliptical taper on the axle which has been successful however costly to produce at mass.

[Pari]

Unfortunately that makes a weak spot in the middle of the axle where the axle will fold. I'd suggest making the carbon continuous and gluing a retainer in the middle. Its' only purpose is to prevent the axle shifting if it is bumped from the side.

CKB has been doing this with carbon sleeved stainless. They also tried elliptical taper on the axle which has been successful however costly to produce at mass.

Point taken on a weak spot in the middle, it crossed my mind also. A continuous tube is preferable, but I had it in my head that the center disk acted as a resistance within the chamber against the bushes as well as centering the axle.

I came across these on the net and thought they might also work for securing the center disk, But didn't find any more info on this site so the images are tiny thumb nails.

something like a this but with a headless screw, even just one screw. (The assembly just gets more complicated and I wonder if it's worth all the effort and expense! But I am seriously inquiring about having these things made, so I continue to try and find a way of having my cake and eating it. e.i, a light weight Revo based truck that's easy to replicate.)

[airjunkie]

Hi

ill get some pics up for ya

yes the retainer in the middle is just to stop it shifting left or right as has already been said. . .

but even thiough this is the case it will still have huge forces applied to it so if glued it would need to be quite strong

[Pari]

Thanks for that,

I look forward to seeing them.

[Guster]

That clamp you circled looks tidy. It won't damage the surface of the carbon axle by afixing like the others, though might over time wear into it. If all you wanted to prevent is the axle moving sideways, I'd rough up the surface with some sand paper and wrap a roving of glass or carbon wet with epoxy so it forms a little ridge. If you do it between two tight fitting stainless washers it can be made quite tidy.

[SoutherlyBuster]

Since you are putting the steel rod inside the hollow CF rod, you will be developing circumferential stresses as well as the usual bending induced stress along the axis. A lack of circumferential fibres will mean it will break rather quickly duing to the circumferential stresses. So you need to source some rods with circumferential wraps as well, ie a mix of 0 and 90 degree wraps. I have experienced this first hand with a two liner kite.

[Pari]

Since you are putting the steel rod inside the hollow CF rod, you will be developing circumferential stresses as well as the usual bending induced stress along the axis. A lack of circumferential fibres will mean it will break rather quickly duing to the circumferential stresses. So you need to source some rods with circumferential wraps as well, ie a mix of 0 and 90 degree wraps. I have experienced this first hand with a two liner kite.

Looks like I've opened a can of worms with this design!

So what exactly does that mean? Are you saying that there should be more that one sleeve with opposing weaves, or would a diagonal weave be best, were it crossess the length of the tube at 45 degrees?

That clamp you circled looks tidy. It won't damage the surface of the carbon axle by afixing like the others, though might over time wear into it. If all you wanted to prevent is the axle moving sideways, I'd rough up the surface with some sand paper and wrap a roving of glass or carbon wet with epoxy so it forms a little ridge. If you do it between two tight fitting stainless washers it can be made quite tidy.

I not likely to ever make these trucks myself. I would be inclined to have them made for me by some prototype place in China if I was to make them at all. Really this is more a design experiment I'm hoping someone will run with (or not)!

So I don't think messing around with carbon fiber is on the list, but rather I feel more comfortable with a more machined components way of building it. So far everything is easy to make: tubes, bars, straight forward CNC parts, bushes etc. And the center retainer could be machined without to much effort (i hope).

Please remember guys, I'm no engineer, and not tooled up to get my hands dirty. But I do work in an industry were I'm use to dealing with using factories in China to get s---t made.

So I'm coming from that mentality.

It would be interesting to work out just how much the finished product would weigh compared to a normal Revo truck!

[SoutherlyBuster]

How many 0, 90 and 45's well I would have to do an analysis to determine that. There are other reasons for having a mix of 0, 90 and 45 layers, the type of failures that are insignificant if a good mix is present but can be a major reason for failure if a mix of 0,90 and 45 degree layers are not present. It's ok to have it say 0 degree dominant, then put in some 90 and 45 layers. Also make sure you have a symmetrical layup, ie mirroring what goes from the bottom layer to the middle layer, to the top layer to middle layer.

The other problem with a hybrid design of metal and composites is thermal expansion. CF has a very low thermal expansion rate compared to steel and Aluminium, so if you have a tight fit at room temperature then let it bake out in the sun, the metal part expands out and may crack your outer CF tube --- another reason to have some circumferential layers. Have loose fit and well you get a rotten ride.

You really need to tabulate your weights and decide where most of the weight lies and then decide if a material change will be of benefit.

Regards,

Norman.

[Pari]

How many 0, 90 and 45's well I would have to do an analysis to determine that. There are other reasons for having a mix of 0, 90 and 45 layers, the type of failures that are insignificant if a good mix is present but can be a major reason for failure if a mix of 0,90 and 45 degree layers are not present. It's ok to have it say 0 degree dominant, then put in some 90 and 45 layers. Also make sure you have a symmetrical layup, ie mirroring what goes from the bottom layer to the middle layer, to the top layer to middle layer.

The other problem with a hybrid design of metal and composites is thermal expansion. CF has a very low thermal expansion rate compared to steel and Aluminium, so if you have a tight fit at room temperature then let it bake out in the sun, the metal part expands out and may crack your outer CF tube --- another reason to have some circumferential layers. Have loose fit and well you get a rotten ride.

You really need to tabulate your weights and decide where most of the weight lies and then decide if a material change will be of benefit.

Regards,

Norman.

Ok, the whole expansion thing is something I can get my head around and hadn't thought about... good point. So how would a completely CF axle work? Rod and tube, or would that be unnecessary? Could it just be fabricated from scratch? And what would be the issues with an axle like that apart from being very expensive? Would it be possible to add the screw thread on a CF rod axle?

Thanks for the feedback guys, I'm learning from this thread.