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View compareFrequently Asked Questions
Questions? We have answers.
Who is R Theory Cycleworks?
We are a bike parts company in Markham, Ontario, Canada. We design mountain bike parts. We bring similar engineering concepts and design philosophy from our motorsports sister brand.
I run a bike shop. Can I sell your parts?
Visit our Become a Dealer page to apply.
How do I reach you?
Email support@rtheorymotorsports.com. You can also visit our contact page.
Find your fit
Frequently Asked Questions - Adjustable Cranksets
How do I pick the right crank length?
Most bikes come with 170 mm cranks. That is the most common size. But one size does not suit every rider. Start with the length you ride now. Then change it by 5 mm. Ride a few times before you decide. Your body needs time to get used to a new length. A bike fitter can help too.
Why choose an adjustable crankset?
One crankset gives you eight lengths. They run from 140 mm to 175 mm in 5 mm steps. You can test a few lengths without buying a new set each time. It also helps when two riders share one bike.
Does crank length really matter?
Crank length changes how far your legs move with each pedal turn. Some riders feel more comfort at a different length. Studies on crank length and speed show mixed results. So we do not promise a speed boost. We made the GR7 and TR8 so you can find the length that feels best to you.
Which one do I need, the GR7 or the TR8?
The GR7 is for gravel and road bikes. The TR8 is for cross-country and trail bikes. Both adjust from 140 mm to 175 mm.
Will it fit my bike?
The GR7 fits a 24 mm Hollowtech bottom bracket. Its axle is made for standard Boost frames. It uses 3-bolt direct mount chainrings. Its Q-factor is 170 mm. That is how far apart your pedals sit. The TR8 fits modern Boost frames too. Not sure about your bike? Contact us before you order.
Does it come with a chainring?
The GR7 does not come with a chainring. Chainrings are sold on their own in our chainring section. The GR7 is set up for one chainring. It can also take two with a SRAM spider. For one chainring, we suggest a 6 mm offset.
Built to last
What if it breaks? What does the warranty cover?
Every part we sell has a lifetime warranty. Parts that fail because of how they were made are covered for life. Crash damage is covered for life too. Bolts and small parts are covered for 3 years from the day you buy. Normal wear is not covered. That means bearings, bushings, scratches, and faded anodizing. Bad installs, changes to the part, and abuse are not covered. Lost or stolen parts are not covered. The warranty is for the first owner only.
How do I make a warranty claim?
Email support@rtheorymotorsports.com. Send your receipt, photos of the problem, and a short note on what happened. If we have the same part in stock, we will send a new one. If not, we send the closest match.
What is it made of? How heavy is it?
The GR7 is made of 7075 aluminum with a hard anodized finish. The axle is chromoly steel. The bolts are Grade 12.9. It weighs 884 g without a chainring. We chose strength over the lowest weight.
Buying and shipping
Is shipping free?
Yes, in Canada and the USA. Ground shipping is free on all orders there. Other countries pay a rate you see at checkout. Faster shipping costs extra. We usually process orders in 1 to 2 business days. Delivery time depends on where you live. It also depends on the shipping you pick.
Can I return it?
You have 30 days after your order arrives. Email support@rtheorymotorsports.com first. The part must be unused. It must be in its original box. Send your receipt too. If we accept the return, we send you a label. Your refund goes to your original payment method. That happens within 10 business days after we approve it. Sale items and gift cards cannot be returned. To swap an item, return it. Then place a new order.
What if my order arrives damaged?
Check your order when it arrives. If it is damaged, faulty, or the wrong item, email us right away. We will work to make it right.
How can I pay?
We take Visa, Mastercard, American Express, Discover, Diners Club, PayPal, Apple Pay, Google Pay, and Shop Pay. You can shop in Canadian or US dollars. Pick your country in the menu.