Slow progress but progress (DIY two seater tadpole trike, 9hp Honda diesel)

[MetroMPG]

Glad you got it home safe.

[redneck]

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Good deal.

That will help speed up the process.

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[user removed]

Next issue, the rear tire. The OE Harley tire is a 165-70-17. I don't want to use a motorcycle tire or it will just wear out quickly in the center. I also can not use a tire whose section width is more than about 6.5 inches. The motorcycle tire on the wheel now is about 6.5 inches in sectional width and the clearance between the tire and drive belt is practically nothing, maybe 1/8th inch (no belt yet). It seems like the best solution I have found so far is a tire made for antique cars available from Coker tire, a 550R17 with is recommended for a 5 inch wheel (which is right), with a sectional width of 5.5 inches and tread width of 4.5 inches. It will cost me $250 for one tire.

The diameter is 28.5 inches which will lower the overall final drive ratio with 708 revolutions per mile.

regards
Mech

[HydroJim]

Summit racing was the best source I could fine for odd tires. Coker is usually the brand that carries something that'll fit on a motorcycle wheel but you might find another brand. I'd try to find something cheaper than $250 but maybe you already looked. If the car is chain drive you can pretty much use any height tire and adjust the ratio with the sprocket. But again, I'm sure you already know.

[Giovanni LiCalsi]

Can you please post a photo of rim?
Is it a motorcycle rim?
If so, would the Coker tire seat in the rim securely?
Have you looked at some of the touring motorcycle tires?
Some have an aggressive tread pattern for longer wear.
Here is the Coker 550R17" radial tire.

Thank you

[user removed]

Two pics of the rim and clearance. The rear suspension is a Harley Softtail which was purchased as a unit with the transmission. The alignment and geometry is pretty much fixed so I can use the belt drive from the Harley.

[user removed]

I've spent a good bit of time coming up with this solution. The tire calls for a tube but I think that is more of the rim than the tire since the tire is intended to be used on a rim that is probably more than 70 years old. While the price is high,when it offers the only solution, other than a complete redesign.

regards
Mech

[redneck]

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I poked around on the Harley forums and found that a 205/50R17 car tire should fit your soft tail.

One of the key issues in running a tire this wide is that it comes so close to the swing arm is sidewall flex. The way to eliminate this is by using a tire that has a Z or a Y rating. These high speed tires have an extra layer of belt in the sidewall which virtually eliminates flex.

Maybe you could find a used tire at your local pick & pull and try it first to see if it will clear properly, then order a new one.


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[redneck]

Originally Posted by Old Mechanic

Two pics of the rim and clearance. The rear suspension is a Harley Softtail which was purchased as a unit with the transmission. The alignment and geometry is pretty much fixed so I can use the belt drive from the Harley.

Old Mechanic

I've spent a good bit of time coming up with this solution. The tire calls for a tube but I think that is more of the rim than the tire since the tire is intended to be used on a rim that is probably more than 70 years old. While the price is high,when it offers the only solution, other than a complete redesign.

Here's another idea.

You could notch the swing arm and frame if necessary for tire clearance. Just weld a plate in the notch, thus keeping the structural integrity and strength of the tubular design. No redesign necessary.

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[Christ]

A 205/50R 17 Wil have a section of 205mm... which is about 7-8 inches. Mounting it on a 5 or 5.5 wheel will bulge the center and can cause the beads to twist and not seat properly.

He'd be looking for a metric 17" tire in about the 155-185 range.