I figured some folks might only visit specific forums and I'm trying to get exposure, for quick answers...as everything is scheduled to go out for powder coat and paint today.

 

That may have been the right answer to my problem but I'm probably too far into this to make that particular change now...

 

Lucky for you I have combined them so your answers aren’t spread out all over the place.

 

Sure. First I would start with asking people on HD Forum if they think your engine combo and estimated power output will smoke the tire just by whiffing on the throttle. Chances are you won't find many people here who will agree it will. Also, how will your 124" deliver power? Torque monster or high RPM power? Both are hard on tires but the torque monster will break traction easier than the higher RPM power because of how the power pulses hit the tire contact patch compared to the vehicle's speed at the time you go WFO with the throttle.

Second, there are many tire options out there, some softer than others. Yea they won't last as long but do you want traction or tire life?

Ultimately I would go with the engine you want and leave the chassis alone. If you MUST have a fatter rear tire, trade your bike in before you swap the engine for the newer models that come with a 180mm rear tire because doing that to your era bike will probably end up being more expensive.

 

Now I understand why this question is "time sensitive".

Respectfully, where do you expect to go with this? I take it you hired out this project to someone. He is giving you an answer you don't like, or are at least second guessing.

Is it your plan to go back to him with a bunch of internet forum opinions and expect him to change his mind? That seems like a recipe for disaster to me.

I assume you put some time, thought, and effort into choosing your builder. You are no doubt spending a fair amount of money on this, so you chose carefully. And judging from what you're saying, the bike has already been fully mocked up, and is ready for teardown, final finish, and reassembly.

This is the wrong time to be asking about basic architecture questions. The time for that is at the beginning, and I assume your builder has already considered all these issues.

This has a "change horses mid-stream" feel to it. I really don't have any advice for you other than this: Ask yourself whether or not you trust your builder. Yes or no. Answer that question, then proceed accordingly.

 

I appreciate the input...and you are correct about it being more expensive. It looks like I'll be putting somewhere between $20k-$30k into this build. I agree with running softer tires. I do that now. This is a high rpm motor but it also puts down some torque, hence my concerns. When the build is finished, I'm expecting 135-140 hp and I'm concerned about not having enough rubber on the ground for all around handling...and spinning that tire out when I don't want to.

My concern is the fact that I'm already investing a HUGE amount of money into building my dream bike...and I'd like to get her right, from the start. Paint and powder coat are never going to match if I have to make these alterations down the road. It seems as if it may be wise to drop another $2k in the build now, than to have to spend another $6k (or more if an entire paint job is required; paint alone, is costing me $5k) later, fixing what I should have done in the first place.

 

I think I do...just not sure if he's considering all of the options. I'm seeing these wide rear tire kits online and it appears as if they MAY solve my problem, but then again, I'm no expert in the mechanics of it all. I'm just concerned about not having enough rubber on the road...and if there's an option to fix that available (for $2k), I'd rather drop it now than to wish I had. He may be thinking more about the total cost, where I'm thinking about my once in a lifetime build.

 

Have you put it to him in exactly those terms? "I'm worried we don't have enough tire, and if it costs another $2k to get there, I'm willing to spend it."

What did he say?

 

No, but perhaps I should.

 

Not required
the op ( and myself and many others) already has a 150 with stock belt and fender,

usually the only requirement is spacing the rear pulley outboard 1/8.th inch