Topic: Does anybody make a 4" slick to fit a 15" rim.

[MRieck]

 For a Mouldon framed dragster. Just as a preemptive measure... spacing out, pulling in, alien technology etc etc etc will not work.
 Thanks guys.

[gschuld]

Mike,

Was that a mistake in the title?  From what I understand, 18" slicks ruled early on.  By the time guys started needing wider slicks(like 6" and over), most went to narrow car slicks and swapped to 15" rims.   The vintage early 70s style 4" slicks were all for 18" wheels, or so I thought.  The repop M/H Racemaster below sure is anyway.   The ideal rim is an 3" bead to bead. RC Engineering sold complete Barnes quick change disc hub rear wheels with a 3" width alloy rim for just that purpose.  That would probably be the ideal period correct rear wheel for the Muldoon chassis. 

For those that do no know, the dragster below in the RC catalog is a very early Muldoon lay down chassis, and a friend of Mike is getting it ready to run again. 

This is something to celebrate...

George

[MRieck]

 The current rear rim is a solid 15" piece George. Maybe he will have to go with a different rim

[gschuld]

Mike,

  This is the RC built Steakley double at Bowling Green, Kentucky 1973.  By late 1972, RC was using custom Kosman two piece bolt together rear wheels.  No holes in the sides, just the perimeter bolts.  I believe the rims were 15"(rather than 16") and were made to use car tires, 6" minimum I'd think.  But this for the doubles.  The easiest fat tire single sohc I can recall was a custom made single running a big bore on nitro.  This was about 1973/74.  I can find it if that helps.

IMHO, the repop 18x4 M/H Race master slick above would represent THE period correct tire for a 1970-1972 Ralph Muldoon chassis, assuming 1970-73 is the time period of interest.  Many small tire drag bikes ended up using 18" road race slicks(like the Goodyear roadracer) by the mid 70s. D&K offered 15" or 16" Kosman style rear wheels for their single lay down chassis by 1975, not sure but I think the width was around 3.5.  Not sure what tire you could put on it now.

It all depends on what your friend is looking to do.  But as fast as I know, there are no 4" wide slick options today for a narrow 15" rim.

The simplest method is to lace up a 2.5 to 3.5 wide(3" ideal) alloy 40 spoke 18 rim to a factory drum hub (check the RC dragster above).  But a spool hub, 3" Barnes dirt tracker style would be the top shelf option.

George

[gschuld]

Don Land custom built a "B fueler" lay down in 1973.  It used a 997 RC big bore, hilborn, ARD, nitro, and a Kosman two piece rear wheel with a 6" wide Racemaster slick.  That was considered to be a big rear tire for a single lay down at the time.  But it was running NITRO...

I couldn't get the article up since the security flagged it for some reason.

George

[gschuld]

Hopefully these will make it through.  Interesting that this Kosman rear wheel on Don Land's dragster has the +/-2" lightening holes around the perimeter.  Most were solid back then.

George

[gschuld]

A late 70s vintage sohc wheel/tire combination, common in the early Prostock class.  Vintage DID 3.5x18 aluminum rear rim laced to a factory drum hub, with a "Goodyear Roadracer" 18" slick on it.

Not light though, 45lbs total with solid alloy 54 tooth sprocket.  Non cush spoked spool hub wheels were certainly lighter.

George

[gschuld]

A late 70s vintage sohc wheel/tire combination, common in the early Prostock class.  Vintage DID 3.5x18 aluminum rear rim laced to a factory drum hub, with a "Goodyear Roadracer" 18" slick on it.

Not light though, 43lbs total with solid alloy 54 tooth sprocket.  Non cush spoked spool hub wheels were certainly lighter.

George

[gschuld]

This was RC's first double engine top gas bike.  Built later 1972.  Broke a few national records with Russ driving, and really pissed off some of his Harley and Triumph competition.... 

Kosman solid wheel. 250 compound tire.

George

[MRieck]

I was talking to Stetson today and it looks like a new wheel is in order. thanks for the info on the M/H repop slick George. Rick thanks you too.

[Retro Rocket]

Why not lace up or use a 17 inch rear rim ? Lots more options for tires. If he's using the stock size rear CB 750 axle , the GSXR 750J and GSXR1100K both use a 4.5 x 17 inch rear 3 spoke rim using the same axle size as the Honda, all you have to do to make it work is sort out spacers and machine a bit off the sprocket carrier to get the chain line right, it is a rear disc wheel as well...

[gschuld]

Mike,

No problem.  I think a bunch of vintage drag bike guys got together and pestered a manufacturer to pull out the 40 year old mold and start reproducing the 18x4 M/H Racemaster, but with modern sticky rubber.  I know vintage dragbike group was trying to drum up interest in putting together a series based around that tire as the spec tire.  I don't think anything came of it, but atleast those who gave 60s though early/mid 70s dragbikes have a really nice period correct tire to use. 

Stetson owns the Muldoon?  That's perfect.  What does he plan to do with it?  Nostalgia events?

So when do you suppose the 836 will start feeling too modest and a fresh big bore motor gets under way....
 
George

[gschuld]

Mike,

For reference, the first photo is the wheel RC offered in their 1972 catalog.  The second photo is from their 1976 catalog.

George

[gschuld]

Both Ralph Muldoon aluminum chassis.  The pepco blower bike is the very early RC Assassin(slightly different rear frame bracing).  The other is the more common rear layout Muldoon chassis(you can clearly make out the Cobra badges on the cam cover in that photo).  Both are running 18x4 slicks.


The slicks mention was from the 1972 RC catalog.


George

[jweeks]

Coker Tires has the mold for the 4" wide 18" slick. You can buy it from them or M&H. It's a fairly tall tire. I've seen that tire run a 6.6/112 mph in the 1/8th mile this season at my local track. I run it on my 1984 GPZ1100 using the GPZ750 rear rim (18"). It will hold the power for a 10 second run. It may handle a 9, but I wouldn't want to be the driver. When it breaks loose going down the track, it would be difficult to save.

[Don R]

 My drag bike has a 16X5 for looking at, If I make a pass it will use a 17 with a sticky shinko.

[MRieck]

Mike,

No problem.  I think a bunch of vintage drag bike guys got together and pestered a manufacturer to pull out the 40 year old mold and start reproducing the 18x4 M/H Racemaster, but with modern sticky rubber.  I know vintage dragbike group was trying to drum up interest in putting together a series based around that tire as the spec tire.  I don't think anything came of it, but atleast those who gave 60s though early/mid 70s dragbikes have a really nice period correct tire to use. 

Stetson owns the Muldoon?  That's perfect.  What does he plan to do with it?  Nostalgia events?

So when do you suppose the 836 will start feeling too modest and a fresh big bore motor gets under way....
 
George

No......Rick doesn't own it......a longtime friend of his. It has a newly built, hot 836 engine in it. Just needs to get the rear wheel sorted and new fork tubes (looks like they are from a CL125 or something). Front brake is about a 5" drum.....the final word in braking.
 Personally I think the 836 engine is the perfect size for that frame.....not to much power but enough to get an 18 lb frame moving

[MRieck]

Why not lace up or use a 17 inch rear rim ? Lots more options for tires. If he's using the stock size rear CB 750 axle , the GSXR 750J and GSXR1100K both use a 4.5 x 17 inch rear 3 spoke rim using the same axle size as the Honda, all you have to do to make it work is sort out spacers and machine a bit off the sprocket carrier to get the chain line right, it is a rear disc wheel as well...

That's a good suggestion Mick but the frame is so narrow I don't think it would even take a 5" tire. This thing is old iron.......I mean aluminum.

[754]

 The two piece wheel on Lands bike, might be one of the monocoque wheels or a jongbloed..

 I got a wide wheel coming from my buddies sortster, think it is a 15 with a 180 on it.. street tire but it stuck well.. would wheely to 90 mph..  I suspect if you got a Shinko that fit the rim, it would grab good..

[gschuld]

Did you get my email about the Ebay wheel Mike?

George

[Retro Rocket]

Why not lace up or use a 17 inch rear rim ? Lots more options for tires. If he's using the stock size rear CB 750 axle , the GSXR 750J and GSXR1100K both use a 4.5 x 17 inch rear 3 spoke rim using the same axle size as the Honda, all you have to do to make it work is sort out spacers and machine a bit off the sprocket carrier to get the chain line right, it is a rear disc wheel as well...

That's a good suggestion Mick but the frame is so narrow I don't think it would even take a 5" tire. This thing is old iron.......I mean aluminum.

Hi Mike, the wheels i mentioned fit into a stock 750 arm if that helps....

[Medyo Bastos]

how about a radial?