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Thunder Roadster operational costs

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On ApexSpeed.com I've been conducting a survey of operational costs for each class.


Here I'm only looking at the predictable costs that vary between the classes. I'm not trying to calculate total operational costs.


Some costs are more or less the same between classes, such as towing, hotel, food, entry fee, and so on. I am ignoring those costs.


Some costs are personal choice, and not inherent in the class, such as how much you choose to spend on your tow vehicle or RV, or paying people to support you. I am ignoring those too.


Some costs, while having some correlation to the class, are unpredictable and so difficult to quantify, such as crash repairs or engine failures. I am ignoring those too.


That leaves me with:

  • tires
  • engine rebuild (by a professional)
  • gearbox rebuild
  • fuel
  • brake pads
  • other, depending on the class


I guess there are other smaller but predictable maintenance costs, such as oil changes, brake rotors, brake fluid, etc. If you think the Thunder Roadster has above or below average expenses in these areas, let me know, and I will include them.


Drivers from many of the classes have responded with data for their class, and the result is:


a spreadsheet in Google docs


Here's what I have for the Thunder Roadster. Some of these numbers are just place-holders that I made up, and are completely inaccurate. Most of this data comes from thunderroadsterseries.com. If you have changes, please reply below, and I will update the spreadsheet.


Class name: LTR

Engine make: Yamaha

Engine model: XJR

Displacement: 1250

Power at crank, HP: 138 (120 at the wheels)

Torque at crank, ft-lbs: 86

Weight with driver, lbs: 1,500

Purchase new, $: 30,000 turn-key, pro build

Purchase used, $: 15,000 nationally competitive

Tires set, $: 500

Tire competitive heat cycles: 40

Engine rebuild, $: 3,500

Engine competitive hours: 40

Fuel $/gallon: 3.00

Fuel gallons/hour: 6

Brake pads set, $: 275

Brake pads hours: 27

Gearbox rebuild, $: ?

Gearbox hours: ?

Other operational costs, $:



Regarding the engine, here's the scenario: You have a fresh engine producing power that is competitive in a Majors race or the Run-offs. It produces this power for some amount of time, and then starts to fall off, and at some point is no longer competitive. You send the engine back to the builder, who does whatever is necessary for that particular engine (some classes more, some less) to make it competitive again. How much does the builder charge for this? And how many hours did the engine operate competitively before becoming non-competitive?





Greg Holmberg

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There's been a big move to Gen II 'Busa engines for increased reliability as a lot of the newer Yamaha engines were having issues with breaking cranks, and they aren't that cheap, especially to massage to 130-140 horsepower. (New as in new from 600 racing. It's an OLD bike engine that hasn't been used in a new bike in a LONG time.) The 'Busa engines are pretty-much bulletproof and we've (Southeast group) only lost a handful of 'Busa engines and they've been caused by operator error.

Some restrict them with small carbs to stay under the 140rwhp limit. I believe the stock TR rules are something like 12.3 lbs/hp with a max of 140. A lot of us wanted to run FI for the tuning ability that allowed you to get to 140 and then pull timing and fuel from the ECU to stay there and have an incredible curve. Our group (TRX) has since gone back to a stock ECU (168-170) in order to make it easier for people to buy and engine and drop it in without having to know someone that can do the tuning and remap the ECU. We check ECU's at random to verify the stock tune, and reserve the right to put anyone's car on a dyno at any time if anything "funny" (internal modifications) are suspected, but we've never had any instances leading to this and the cars are INCREDIBLY even.

I'll admit, the conversion to 'Busa power isn't the cheapest (mounts, oil pan, radiator, oil cooler, accusump, wiring harness, etc), but once it's done, it's MORE than worth it. Not to mention, then engines are plentiful and can be found for cheap on ebay out of wrecked bikes. Of course you have a chance of buying a lemon this way, but that goes for anything. Most of us didn't want to take that chance when getting started, so we bought full motorcycles, pulled what we needed and sold the rest back off.


As for the rest of your prices, they're pretty spot on.

I can't remember the exact price for brake pads, but it's less than $275 for our Brembo brakes. I want to say about $100-$125 for front or rear. I'll prettymuch use 2 front sets in a season, but will go more than a season (maybe 2) on the rears.

You can go multiple seasons on the rotors without issue and they're cheap too.


Oil change on the Yamaha was like $35. 'Busa is about $80, but we do the 'Busa every other weekend, so it balances out.


Rear diff lasts about a season and a half and a complete set-up, installed in the housing with the gears polished is something like $750 or so.


Replacement body panels are super cheap.

Since it's a tube frame car, front and rear clips can be cut off and replaced.

All of the suspension and steering (other than the actual coilovers and steering box) are rods and heims, so again very cheap and easy to replace if you happen to make a mistake that ends badly.


If you talk about a fun to drive car (light weight, spool/welded rear end/sequential box), great competition, and lap times that are usually equal or better than the vast majority of race cars (of all classes) over any given weekend, then the low entry price and absurdly low running costs, I can't think of anything I'd rather be in.

Not to mention, the safety factor being that it's a tube frame race car from the ground up.

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Very good. Thank you, TowDawg.


I entered those numbers in the spreadsheet. Total per weekend (8 sessions, including Friday practice) for tires + engine + fuel + pads + gearbox + rotors = $549. One of the cheapest classes on the list!

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Sweet post! Its hard to get much action here. I'm mostly just TR curious and lurking, but is there an online forum that gets more hits in terms of TR information?


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Give Randy at TRV Racing or Gary Tinker at Toys by Tink a call if you need more info they are the best places for info on the car. There is no forum anywhere on the car which is shocking as there are forums for everything. Feel free to PM me as well if you have questions.

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