Converting an Older Rim-Brake Road Bike to Wireless Electronic Shifting: What to Check on the Frame First

A steel frame with gold decals on the down tube. A 2017 Trek Emonda SLR still wearing mechanical Ultegra. A Felt that's about to get a new drivetrain. This week several riders told us they're doing exactly this: keeping a good older frame and swapping the cable shifting for wireless electronic. Several of the questions were about the hanger, the front derailleur mount and the chain.

That's the right instinct. On an older bike the parts that decide whether the conversion goes smoothly are the rear hanger, the front derailleur mount, the cassette and the chain. Here's what to check, in the order we'd check it.

1. The rear hanger: look for the step

This is the one that catches people out. Before you fit the rear derailleur, look at the hanger:

• The hanger must be straight. Seen from behind the bike, it should sit parallel to the cassette. If it's bent, straighten or replace it first.
• The bottom of the hanger needs a step. The small tab next to the derailleur's mounting bolt has to sit on that step before you tighten the bolt. That's what lets the derailleur swing back and forth like any other.
• If the step is too small, use a hanger with a bigger step, or add a hanger extender.

A correctly fitted WHEELTOP derailleur floats back and forth just like any other. If yours is stiff, check first that the tab is sitting on the step of the hanger.

What if the hanger is built into the frame and can't be swapped? That doesn't mean the project is dead. An extender bolts onto the existing hanger, the derailleur mounts on the extender, and the tab rests on the extender's step. One buyer with a steel frame like this sent us close-up photos of the hanger, and decided to buy an extender, in gold to match the lettering, just in case. If you can't tell whether your step is big enough, photograph the hanger from directly behind the bike, looking forward along the chain. A side-on photo hides the step.

2. The front derailleur: braze-on or clamp

The TX is a 2X system, so the front derailleur comes with it. It uses a braze-on mount. If your frame has no braze-on tab, a clamp-on adapter can be used on a round seat tube. We can supply one: message us before or after ordering. One buyer reviving an older bike asked for exactly that clamp, for a round tube.

When you set it up, put the chain on the big ring and aim for the outer guide plate to sit 1 to 2mm from the chain. The 2mm support screw tilts the cage until it's parallel with the ring. If the cage tail ends up pushing into the big ring's teeth, even at its highest position, check your chainring size. Frames designed around a 50/34 can struggle with a 53T big ring. Adjust the support screw first; if that's not enough, a taller braze-on adapter or a 52/36 or 50/34 chainset solves it. If you're fitting a larger big ring than the frame was designed for, for example 53T on a 50/34 frame, check this.

3. Cassette: size and speed count

• The TX takes cassettes up to 36T. An 11-34 sits inside that limit.
• Speed count isn't fixed in the hardware. You set it in the WHEELTOP app under Flywheel settings, so an 11-speed cassette gets set to 11 and a 12-speed to 12.
• A new cassette deserves a new chain. Check the old cassette before you reuse it: sharp, hooked or leaning teeth mean it should be replaced together with the chain, otherwise the new chain can skip under load.

If you're running a SRAM 12-speed cassette, we covered the app setting and calibration in this article.

4. Chain: match the speed, then size it

The chain speed has to match your cassette and shifting system. One buyer fitting a 2022 Felt road frame asked whether we had an 11-speed chain. We do: the CHOHO fully hollow flat-top chain comes in 11-speed (Z11-DSL, 120 links, 259g) and 12-speed (Z12-DSL, 128 links, 266g), each with a pair of single-use quick links. The 11-speed works with Shimano 11-speed cassettes and chainrings; the 12-speed with Shimano and SRAM AXS 12-speed. It fits the TX with the standard pulley cage, but not the ceramic carbon oversized pulley cage.

To size it, any one of these works: lay it next to the old chain and cut to the same length; run it round the biggest ring and biggest cog (not through the derailleur) and add 2 links; or check that with the chain on the big ring and smallest cog, the derailleur cage hangs at 90° to the ground. Then thread it through the cage on the guard-plate side of the chain-retaining pin, otherwise it will rub and catch.

5. Brakes: rim-brake levers keep your calipers

The rim-brake version of the TX levers pulls a standard brake cable, so they work with the rim-brake calipers already on your bike. The standard rim-brake kit doesn't include calipers. The full-groupset rim-brake bundle, the TX 2x11 kit, does include MEROCA BR-R7000 dual-pivot calipers, plus crankset, bottom bracket, cassette and chain, if you're replacing all of it. The bundle's bottom bracket is threaded BSA, 68 to 73mm, not press-fit, so check your shell too.

What to expect on the day

The kit is shipped switched off. Touch the magnetic charging cable to the rear derailleur to wake it. It's already paired, so you only re-pair if you add or replace a part. One TX buyer put it like this:

Not installed but came paired

After the mechanical side is done, do the initial calibration with the chain on the big ring and the rear on the smallest sprocket, and keep turning the cranks while you do it. Don't calibrate while riding. A customer who fitted the TX groupset to his son's bike said:

Install and tuning were dead simple.

To be fair, not everybody found the fine-tuning instructions easy. A customer who bought the OX 2.0 wrote:

Instructions weren't the easiest to understand for fine tuning and the new app has the fine tune adjustment + & - cut off the screen.

If you're not used to this, the manufacturer suggests having a bike shop fit it. Either way, after your first few rides, go back over the small screws on the rear derailleur and nip them up; they can loosen slightly as it beds in, but don't overtighten. For common slips, our installation mistakes article is a good second read.

Quick checklist before you order

• Hanger straight, with a step big enough for the tab (or plan on an extender).
• Braze-on front derailleur mount, or ask us for a clamp for a round seat tube.
• Largest sprocket 36T or smaller.
• Chain speed matches the cassette, and the old cassette isn't worn.
• Rim-brake calipers you're happy to keep, or the full bundle if you're replacing them.
• Bottom bracket shell BSA 68 to 73mm if you're taking the bundle's crankset.