RC10Talk - The Net's Largest Vintage R/C Community

i installed the JC Racing 2.2 wheels for the kyosho optima, but i now have another issue. the hexes are a press fit and my rear wheels are slipping and it bugs me. what cvd options are out there for a stock width optima mid? also while i'm at it any mods you guys think i should do for it that i have not mentoned?

The hexes shouldn't slip on the taper shaft if the wheel is tightened with nut, strange

Need to measure length of shaft, lazer I think is 62.5 rb5 is 65.5 mm both have pin drive (hex adaptor ) have fun.

wydraz wrote:The hexes shouldn't slip on the taper shaft if the wheel is tightened with nut, strange

age does odd things to cheap metal

al.48 wrote:Need to measure length of shaft, lazer I think is 62.5 rb5 is 65.5 mm both have pin drive (hex adaptor ) have fun.

i know the mid is 62.5 thats about it

There are cvd's for the rb5 or lazer zx5 whixh are 62.5mm, but they are not cheap at all. There's also 60.5mm ones you can combine with other axle parts and a spacer ... check some threads about the ultimas or you can use the 65.5 mm ones with longer rear arms... if you feel creative

Try this first: degrease the axles and alu hexes well; using moter cleaner or acetone. Then put the axle back and put a little drop of threadlock on the conical part. If possible use the liquid rather than gel type , but more important don't put too much: you don't want this to go in your bearings.
put the hexes on and wheels. Last but not least: use fresh locknuts.

By the way you can also just use dogbones in the rear and use axles with cups ( easy to find from hpi or other brands): with 2mm pins through the hexes.

wydraz wrote:The hexes shouldn't slip on the taper shaft if the wheel is tightened with nut, strange

They do indeed do that, with modern power. I switched over to hexes with cross-pins on all my modded Optimas except one because of this. Perhaps that's why you never see friction-fit hubs on RC cars anymore. Everything uses cross-pins to lock the hubs to the axles.

My particular solution requires buying inexpensive GPM alloy arms that are almost exactly 5mm longer than stock rear arms, then using readily-available inexpensive 3Racing 68mm CVDs for the Lazer ZX-5...you just need to add a few 3mm spacers on either side of the rear carriers to eliminate play, and drill some holes to re-mount the rear stabilizer assembly. It works perfectly that way but is a bit more involved than simply buying CVDs. More details can be found in my CYANide, Barney and OptiMutt build threads.

Coelacanth wrote:

wydraz wrote:The hexes shouldn't slip on the taper shaft if the wheel is tightened with nut, strange

They do indeed do that, with modern power. I switched over to hexes with cross-pins on all my modded Optimas except one because of this. Perhaps that's why you never see friction-fit hubs on RC cars anymore. Everything uses cross-pins to lock the hubs to the axles.

My particular solution requires buying inexpensive GPM alloy arms that are almost exactly 5mm longer than stock rear arms, then using readily-available inexpensive 3Racing 68mm CVDs for the Lazer ZX-5...you just need to add a few 3mm spacers on either side of the rear carriers to eliminate play, and drill some holes to re-mount the rear stabilizer assembly. It works perfectly that way but is a bit more involved than simply buying CVDs. More details can be found in my CYANide, Barney and OptiMutt build threads.

i was reading through them, thinking about exactly that. but i dont want to widen it any wore unless i do a lwb swap, already looks a bit odd on big modern tires with its current swb and making it wider i think would be even weirder to look at

Welcome!

The wheel hexes can slip by all means but if seated properly and mating surfaces are in good shape the friction fit can be quite impressive. one mistake peeps often make with them is trying to seat them using the wheel. If you want a real good seat use a metal spacer and wheel nut to tighten and seat the hex. Also you might need to put a washer on your new wheels as they may be a little thinner than stock which would let the locknut bottom before fully seating the hex. You can also cool the wheel shaft in the fridge and heat the hex with a heat gun and when assembled the shaft will expand as it warms and the hex will contract as it cools.

If you do decide to go cvd the rb5 sp2 62.5 shafts are the way to go with the least amount of mods. kyosho makes different shoulder length wheel shafts as denoted by the number of grooves cut into them. this allows you the use shims and adjust the cvd in or out. Its best to look at some of the other builds to see what I mean. One other thing to note is that until clamping hexes were brought into the picture, pin drive systems were notorious for snapping wheel shafts. Putting a hole in the shaft essentially created a spot half as strong as the rest of the shaft and all the power transferred against the pin. clamping hexes will create a collar effect when tightened and reinforce the weak spot.

I've posted a link to a mid build I did with heavy mods. might help, http://www.rc10talk.com/viewtopic.php?f=30&t=36480

Check out Alcyon's builds too
http://www.rc10talk.com/viewtopic.php?f=30&t=35023

When you get the authorization to post pics you should put some pics up of your Mid

Jester_The_RC_Guy wrote:

Coelacanth wrote:

wydraz wrote:The hexes shouldn't slip on the taper shaft if the wheel is tightened with nut, strange

They do indeed do that, with modern power. I switched over to hexes with cross-pins on all my modded Optimas except one because of this. Perhaps that's why you never see friction-fit hubs on RC cars anymore. Everything uses cross-pins to lock the hubs to the axles.

My particular solution requires buying inexpensive GPM alloy arms that are almost exactly 5mm longer than stock rear arms, then using readily-available inexpensive 3Racing 68mm CVDs for the Lazer ZX-5...you just need to add a few 3mm spacers on either side of the rear carriers to eliminate play, and drill some holes to re-mount the rear stabilizer assembly. It works perfectly that way but is a bit more involved than simply buying CVDs. More details can be found in my CYANide, Barney and OptiMutt build threads.

i was reading through them, thinking about exactly that. but i dont want to widen it any wore unless i do a lwb swap, already looks a bit odd on big modern tires with its current swb and making it wider i think would be even weirder to look at

Here's one more thing to consider; the Optima is notorious for having bad understeer, especially on acceleration. Widening the track, especially with the Barney build, really improved the steering. The alloy arms only functionally add about 6mm of width on each side; barely more than 1 cm total added track width. The fronts are stock width (Maxxum front arms don't change track width). What makes that car look wider is the use of narrow crawler wheels & tires, which have more negative (outward) offset than original wheels...that's where most of the extra width comes from. Looks aside, it definitely helps resolve the understeer issue.

my optima mid has too much steering, no understeer at all

Kyoshojoe wrote:Welcome!

The wheel hexes can slip by all means but if seated properly and mating surfaces are in good shape the friction fit can be quite impressive. one mistake peeps often make with them is trying to seat them using the wheel. If you want a real good seat use a metal spacer and wheel nut to tighten and seat the hex. Also you might need to put a washer on your new wheels as they may be a little thinner than stock which would let the locknut bottom before fully seating the hex. You can also cool the wheel shaft in the fridge and heat the hex with a heat gun and when assembled the shaft will expand as it warms and the hex will contract as it cools.

If you do decide to go cvd the rb5 sp2 62.5 shafts are the way to go with the least amount of mods. kyosho makes different shoulder length wheel shafts as denoted by the number of grooves cut into them. this allows you the use shims and adjust the cvd in or out. Its best to look at some of the other builds to see what I mean. One other thing to note is that until clamping hexes were brought into the picture, pin drive systems were notorious for snapping wheel shafts. Putting a hole in the shaft essentially created a spot half as strong as the rest of the shaft and all the power transferred against the pin. clamping hexes will create a collar effect when tightened and reinforce the weak spot.

I've posted a link to a mid build I did with heavy mods. might help, http://www.rc10talk.com/viewtopic.php?f=30&t=36480

Check out Alcyon's builds too
http://www.rc10talk.com/viewtopic.php?f=30&t=35023

When you get the authorization to post pics you should put some pics up of your Mid

never snapped a single wheel shaft on the 5 pin drive cars i have/do own my wheels were made for the optima mid, so they are not to thin, thanks for the cvd option, and i can post pics so i will later

Jester_The_RC_Guy wrote:my optima mid has too much steering, no understeer at all

Optima Mid is a totally different beast to the original Optima series. I just noticed you mentioned Optima Mid in your first post, not the title...my mistake for overlooking that.

Coelacanth wrote:

Jester_The_RC_Guy wrote:my optima mid has too much steering, no understeer at all

Optima Mid is a totally different beast to the original Optima series. I just noticed you mentioned Optima Mid in your first post, not the title...my mistake for overlooking that.

the rear motor optima did have that issue, so atleast your correct!