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Tacx T4035 Jockey Wheels



If you feel the need to go ceramic with your jockeys, these are arguably the best bang for your buck

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The Tacx T4035 ceramic and teflon jockey wheels are a relatively low-cost entry to the world of ceramic bearings. Easy to fit with options for all major brands of modern mech, they're a good option for slippery jockeys.

Jockey wheels are one of the fastest-spinning things on your bike. Maxed out in 50/11 at 100rpm, arguably the Clapham Omnibus of cycling achievement, your poor jockeys are spinning at 7.57 revolutions per second. Pretty much what your wheels are doing at 50mph, but your wheels aren't also trying to keep a chain pumped with a few hundred watts within around 0.4mm left or right as it engages a sprocket to transfer said wattage. You can have the newest gear cables, the most perfectly indexed rear mech, the straightest hanger – but if your upper jockey wheel has worn teeth or bearings then your shifting and power transfer from chain to cogset will suffer.

> Find your nearest dealer here

Tacx does a wide range of after-market replacement jockey wheels, with prices anywhere from under 10 quid to about 50, depending on the technology and materials used. What I've been testing is the high-end T4035 model with ceramic bearings and teflon material in the wheel itself.

In the box you get two wheels marked UPPER and LOWER, plus a bunch of small plastic adapters to go between the bolt and jockey wheel itself, depending on your rear mech model – Shimano 7, Campagnolo 8, Shimano 8-11, Campy 9-11, or SRAM 'various' for both road and mountain bike.

The process of fitting new jockey wheels is pretty simple, armed with a 3mm hex key, some Loc-Tite and a few minutes' patience. After aligning your hanger, replacing your shift cables and replacing your chain, doing the jockey wheels is arguably the most cost-effective shift-improving performance enhancement you can do.

After cleaning up your drivetrain, drop the chain off the small ring (being careful not to pedal lest it gets stuck betwixt chainring and frame). The actual act of unbolting the old pulley, popping the new one in, drop of Loc-Tite on the thread and screw into place is simple. About 3Nm of torque (ie 'not much at all') and you're done.

Speed costs

Recently the FrictionFacts lab tested the Tacx Ceramic pulleys against many others including the state-of-the-art Ceramic Speed offering. It found from worst to best a whopping 1.3W difference (yes, sarcastic tone there). The £50 Tacx ceramic jockeys came out a thumping, podium steps-to-voiture balai ('broom wagon') 0.044W higher resistance than the £150 Ceramic Speed equivalent. That's a cost to the Ceramic Speed marginal gain of about £2,272 per Watt.

Fundamentally, I couldn't notice any quieter or smoother running or slicker shifting compared with the replaced Ultegra jockeys, which were maybe 1500 miles old. No doubt had the wheels worn considerably, any upgrade would be noticeable.

> How to adjust your gears for smoother shifting

So who are the Tacx ceramic/teflon jockey wheels for? Firstly, I'd say the person looking to save a few seconds off their 10-mile TT time, while not having to explain to their partner the extra £100+ missing from the bank account had they gone with Ceramic Speed.

The other candidate is the person for whom knowing that things are that little bit slicker, that teensy bit easier, will make that 100-mile sportive effort a psychological walk in the park. That's priceless.

Footnote: I'll report back in 1,000 miles time with an update on how they are wearing. If I can tell, that is.


If you feel the need to go ceramic with your jockeys, these are arguably the best bang for your buck test report

Make and model: Tacx T4035 Jockey Wheels

Size tested: 11 teeth, Ceramic and Teflon

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Tacx says: "All Tacx jockey wheels have closed bearings so that they'll not get stuck, show play or squeak while cycling. Tacx jockey wheels are available for 10 teeth, 11 teeth, SRAM Race and SRAM MTB.

"When used on a regular basis jockey wheels will start to show wear and work less efficiently. Cyclists who spend a lot of time on the bike are recommended to replace the wheels once a year. With new wheels the bicycle chain runs smoother and quieter and you will be able to shift gear more precisely."

Tell us some more about the technical aspects of the product?

Ceramic (Si3N4) with Teflon

These jockey wheels are perfect when you want to save as much energy as you can on long distance rides. Decreasing friction was key when developing this product. The bearings are made out of Si-3N4, a kind of ceramic known for its low friction character, and lubricated with grease to minimize maintenance requirements. Teflon is added to the wheel, which reduces friction with the chain. Finally, a low-friction seal is used to reduce friction with the bearings to a minimum. All these aspects together make this a one of a kind jockey wheel with which you can save energy on a long ride, but also with regards to maintenance.

Rate the product for quality of construction:

Very nicely put together.

Rate the product for performance:

They're light and they spin freely.

Rate the product for durability:

Time will tell. But they are looking fine after maybe 300 miles.

Rate the product for weight (if applicable)

Pretty light.

Rate the product for value:

Here they have to win big time, if you want ceramic, that is.

Tell us how the product performed overall when used for its designed purpose

Pretty well so far.

Tell us what you particularly liked about the product

Easy to fit, flexible re-use options.

Tell us what you particularly disliked about the product

More data would be nice, on the benefits.

Did you enjoy using the product? Yes. Well, OK, I couldn't tell. I think I did.

Would you consider buying the product? Let me see how long they last first.

Would you recommend the product to a friend? If they had £40 to blow and wanted the feeling of a little mental boost, sure.

Use this box to explain your score

If you are in the ceramic bearing game, the Tacx option is certainly cost-effective compared with the major Ceramic Speed alternative. That's the only prism to see this through.

Overall rating: 8/10

About the tester

Age: 43  Height: 183cm  Weight: 72kg

I usually ride: Merida Ride 5000 Disc  My best bike is:

I've been riding for: Over 20 years  I ride: A few times a week  I would class myself as: Expert

I regularly do the following types of riding: cyclo-cross, club rides, general fitness riding, mountain biking, Dutch bike pootling

Living in the Highlands, Mike is constantly finding innovative and usually cold/wet ways to accelerate the degradation of cycling kit. At his happiest in a warm workshop holding an anodised tool of high repute, Mike's been taking bikes apart and (mostly) putting them back together for forty years. With a day job in global IT (he's not completely sure what that means either) and having run a boutique cycle service business on the side for a decade, bikes are his escape into the practical and life-changing for his customers.

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