• Announcements

    • TWINSET

      Photobucket Pictures   07/30/17

      Many forum posts have been affected by Photobucket's recent decision to start charging for linking to photos in forum posts (and other places)
      When this happens, it's down to the post author to add their pics to another service or site and edit their posts to show the pics Please don't report posts or threads with dead Photobucket links, there's nothing admin can do about them.   Any posts with a version of the image below (size varies) have been affected by this decision.
Sign in to follow this  
fastfordrc

Optima Mid Universals - Modern Replacements?

Recommended Posts

I'm currently restoring a Turbo Optima Mid as a runner, but after I stripped it down and cleaned it up I found that the front universals were both bent ;) I've tried my best to straighten them, but someone had tried before me and I'm worried that they might be too far gone. From what I can see, the W5061 parts are getting a bit hard to find now (and expensive), so I'm wondering if I have to replace them, are there any modern equivalent parts?

The W5061 universals measure 62mm from the dogbone pin to the universal pin, 69mm from the end of the dogbone to the bearing flange and the bearing part of the axle is 10mm long.

I've looked around at the current Kyosho buggies and found a couple of possibiltities:

The Ultima RB5 has CVDs available for the rear axle, UM510 (62.5mm).

The Lazer ZX-5 has a number of different length CVDs available (for varying the track width as a setup option, I presume). The most likely matches look to be either LA245 (62.5mm) or LA232 (65.5mm)

After a bit more research, it looks like the difference between the UM510 and LA245 parts is that the axle on the Ultima part is approximately 2mm longer between the bearing flange and hex than the Lazer part - the Ultima RB5 uses Lazer ZX5 rear hubs but with a spacer on the axle between the outer bearing and hex (presumably to increase the track width?).

Has anyone had any experience with these parts (such as where Kyosho's measurements are taken from, for instance?). I have read on another forum someone suggesting the UM510 parts for older Lazers, so they may be suitable for the Optima Mid, but based on the information above the axle part would be too long. If that's the case, then the LA245 look a better bet, but I would prefer to know they are the correct length beforehand as they aren't cheap! Alternatively, has anyone got any other suggestions for sources of possible replacements?

Andy

Share this post


Link to post
Share on other sites

Hello,

I have a runner that I have search for replacement parts. It´s not easy to find.

The part W5061 is still available in Swedish hobby shops and cost 470 SEK (Swedish kronoa) Many Optima parts is still available in Swedish shops. The Ultima and Lazer parts I have tried out on my Optima but they are not so good to use. To long or to short and need modification to fit. Try to find W5061 or use the original OT006 I use the W5061 in front and OT006 in the back.

:blink:

Share this post


Link to post
Share on other sites

Bit of an update, if anyone is interested:

I finally got hold of a pair of LA245 CVDs from Japan (they were a lot cheaper there, but I skimped on the postage so they took 2 weeks to arrive). They are very nicely made MIP-style rebuildable CVDs, though they come without any lubrication so need to be disassembled if you want to add some.

They are an almost perfect swap for the W5061 universals, with one small difference - the length from the end of the dogbone to the bearing flange is an exact match for the W5061 parts, but the length of the stub axle from the bearing flange to the hex is approximately 1.6mm longer once the wheel is tightened up (they are pin-and-hex type axles). It is only a small difference which can be easily solved with a bit of shimming (I estimate you could shim 0.5mm on the inner end of the stub axle if you wanted to minimise the increase in track). I have used sanded-down 5x8 plastic bearings between the outer ballrace and hex as a shim for now until I can get some 5mm shims.

Although the Ultima RB5 UM510 dogbone to bearing flange length is the same as the LA245 parts, the stub axle is 2mm longer than the LA245 axle, which would mean that if you used them you would have approx 3.6mm to shim (a bit much, I'd say). Also, the dogbone part of the standard Lazer LA232 CVDs (65.5mm) would be 3mm too long for the Optima wishbones.

On a totally different track, if you order Fibre Lyte shock towers for the Optima Mid, the front one needs to have the lower inner corners radiused with a file or Dremel (a messy job!) for it to clear the diff bearing carriers on the front gearbox. The radius is present on the stock Kyosho item, so I'm not sure why FL haven't picked the difference up by now!

Andy

Share this post


Link to post
Share on other sites

Yes, they are the Optima universals. Unfortunately as far as I know Kyosho America don't take international orders, and with the Shopatron system you aren't actually ordering from Kyosho America themselves but one of their dealers who says they have them in stock (but that is only really checked after you place an order). If you could find out which dealer is saying they have them you might be able to work something out with international shipping, but Shopatron won't tell you that.

Either way, the CVDs are a better solution for a runner than universals, and for the price I got them for actually work out cheaper. Also, it's nice to be able to move on from the interference-fit hexes.

Andy

Share this post


Link to post
Share on other sites

I am not familiar with CVD... What is it and how is it different from dogbones / universals? Can you post some pics? Where did you order them from?

Thanks in advance,

Jonathan

Yes, they are the Optima universals. Unfortunately as far as I know Kyosho America don't take international orders, and with the Shopatron system you aren't actually ordering from Kyosho America themselves but one of their dealers who says they have them in stock (but that is only really checked after you place an order). If you could find out which dealer is saying they have them you might be able to work something out with international shipping, but Shopatron won't tell you that.

Either way, the CVDs are a better solution for a runner than universals, and for the price I got them for actually work out cheaper. Also, it's nice to be able to move on from the interference-fit hexes.

Andy

Share this post


Link to post
Share on other sites
I am not familiar with CVD... What is it and how is it different from dogbones / universals? Can you post some pics? Where did you order them from?

Thanks in advance,

Jonathan

CVD - Constant Velocity Drive. They are similar to universals, but work in a much smoother fashion - with a universal joint, the further the joint is moved off-centre, the 'jerkier' the transmission of power becomes (until if you move it far enough off-centre it locks up). With a CV joint, power is smoothly transmitted throughout the range of it's movement (hence the name 'Constant Velocity'). I think they started to come into RC in the late 80s/early 90s, MIP are the 'big name' in CVDs but almost every RC manufacturer now offers them either as standard or as hopups on their models. They are either sourced from MIP or copies of their'rebuildable' CVD design - the pin that holds them together is held in by a small grub screw, so they can be disassembled for cleaning - see http://www.hpiracing.com/walkthroughs/rebuild-cvd.htm . They were initially quite expensive as they need to be very precisely machined, but the price has come down now to where they have replaced universals as the upgrade from dogbones and cups

I have attached a picture of the LA245 CVD alongside the W5061 universals. You can see they are almost identical in length. The LA245 CVDs are part of the Lazer ZX5 Rear 'Mid-arm' suspension option set, but they can be bought separately. I sourced mine from a Japanese seller on ebay called 'rdvtg'. They were approximately £17 with the slow postage.

Andy

post-2597-1245276752.jpg

Share this post


Link to post
Share on other sites

I swear i had seen somthing like that before , in the bottom of a dirty pile of bits, found this: I only have one, blasted it clean and put a bit of wd40 on for now, maybe of use for somone... how much play should there be, as it may be well worn?

100_1797.jpg

Share this post


Link to post
Share on other sites

Thanks Andy! I've finally acquired enough dogbones to complete my Optimas (1 Optima, 2 Turbos, 1 Mid, and 1 Turbo Mid SE), but some aren't in the greatest shape, and the universals I had back in the day are all either missing or broken. Those CVDs look like they might hold up better than the universals did.

-Jonathan

CVD - Constant Velocity Drive. They are similar to universals, but work in a much smoother fashion - with a universal joint, the further the joint is moved off-centre, the 'jerkier' the transmission of power becomes (until if you move it far enough off-centre it locks up). With a CV joint, power is smoothly transmitted throughout the range of it's movement (hence the name 'Constant Velocity'). I think they started to come into RC in the late 80s/early 90s, MIP are the 'big name' in CVDs but almost every RC manufacturer now offers them either as standard or as hopups on their models. They are either sourced from MIP or copies of their'rebuildable' CVD design - the pin that holds them together is held in by a small grub screw, so they can be disassembled for cleaning - see http://www.hpiracing.com/walkthroughs/rebuild-cvd.htm . They were initially quite expensive as they need to be very precisely machined, but the price has come down now to where they have replaced universals as the upgrade from dogbones and cups

I have attached a picture of the LA245 CVD alongside the W5061 universals. You can see they are almost identical in length. The LA245 CVDs are part of the Lazer ZX5 Rear 'Mid-arm' suspension option set, but they can be bought separately. I sourced mine from a Japanese seller on ebay called 'rdvtg'. They were approximately £17 with the slow postage.

Andy

Share this post


Link to post
Share on other sites
I swear i had seen somthing like that before , in the bottom of a dirty pile of bits, found this: I only have one, blasted it clean and put a bit of wd40 on for now, maybe of use for somone... how much play should there be, as it may be well worn?

There shouldn't be much play at all, when universals wear it's generally around the holes where the pins go through the yokes on each side of the joint. The holes wear and get bigger, until eventually the metal gets too thin around the pins and they break through. That universal doesn't look too bad, though it's obviously seen some use. Although it's the same length and has a taper for the press-on hex, it doesn't look like a Kyosho one - possibly an aftermarket upgrade?

Andy

Share this post


Link to post
Share on other sites

Just a bit of an update, if anyone is interested. The car is now finished and pics can be found in my showroom:

http://www.tamiyaclub.com/showroom_model.a...83&sid=1274

The CVDs only needed shimming 1mm in the end once the wheels had pushed the hexes on fully (I got away with 0.5mm either side of the hub). They are as smooth as silk, and I'm really impressed with the Optima Mid in general - when you drive one you can see why they were so popular for racing.

Andy

Share this post


Link to post
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
Sign in to follow this