Check before you buy

We want you to be really happy with your GTRO Gearbox.
To be sure you’ll be able to install it on your bike, please check the following:


Bottom bracket shell

Bottom bracket shell is the pipe that the axle of your crank goes through. The main thing you need to check before you buy is the BB shell type. GTRO is compatible with all the frames that use 68 mm or 100 mm wide BB shells, English thread.
If you are not sure what BB shell your bike has, you can do one of the following:


1. Ask your bikeshop – they will surely know!
2. Send us:

  • your bike brand name and model name.
  • (optional) few photos of your BB area, from a few angles.
  • (optional) write us what is written on your BB, usually on the BB cups.

Contact Form

  • x

3. Search it on the Internet with a phrase like:
“<your bike brand and model name> bottom bracket”

For example:
“Giant Anyroad bottom bracket” where:
“Giant” is brand name and “Anyroad” is model name.
You’ll probably be directed to the bike’s specs web site.

Most manufacturers provide information on their bike’s bottom bracket model. If you find the specific Bottom Bracket name (in case of Giant Anyroad it is “FSA TH BB-7420”) copy-paste it to Google and search further, on web search or Google Images. If you read that this BB is English / BSA / ISO or you find thread data “BC 1.37 x 24 TPI”, this is ok.

GTRO is not compatible with press-fit BBs (which do not have thread).
If you want to be informed when we launch a new GTRO press-fit compatible gearbox, leave your e-mail here:

Steering cable length

GTRO is delivered with an integrated steering cable.
Its housing has a standard length of 113cm. We checked it with many, many bike models (new and old) and found it to fit. If you have a less common type of a bike (recumbent, trike, small folding bike) you may need to change the cable.

Brake lever

GTRO’s shifter is not integrated with a brake lever. If you’re using a front derailleur shifter integrated with a brake lever, you will need to install a separate brake lever on your handlebar. There’s a great variety of beautiful and functional brake levers available on the market and you will surely find something that fits your bike!

For recumbents and trikes owners

In vertical bikes the chainstay is the natural point of support for GTRO. Usually trikes & recumbents do not have chainstays, so you need to mark option “No chainstay”, when making a purchase on our site. We will provide you with a solution for this.

For e-bike owners

Some e-bikes have so called PAS installed on the right side of the crank axle. It usually should be possible to move your PAS to the left side of the axle (with GTRO there is no space on the right side). If you can relocate your PAS, you can install the GTRO on your bike. Doubts? Just let us know! Some e-bikes have a so called torque sensor installed in their bottom bracket. We will give you our own dedicated BB, so you would need to take the torque sensor out. In this case GTRO is probably not compatible with your e-bike.

For folding bike owners

GTRO is a perfect solution for a folding bike and it’s compatible with most folding bikes. However, some bikes fold in a way that the right crank is in the middle of the bundle after it’s folded. If so, please, send us a photo of your bike when folded & unfolded, as well as model name of your bike – we will let you know if this is compatible.
At this moment we know of two brands of folding bikes that are not compatible with GTRO for some reasons:

  • Brompton
  • Strida models with eccentric BBs