Finally a lightweight mechanical transmission: This is the Sram Eagle 90 SL drivetrain

"You can hardly change gears more precisely" was the title we gave the Sram Eagle 90 Transmission groupset after our in-depth test. Crisp and yet smooth, even under load: with the Eagle 90, shifting via the shift cable is really fun. We have already found words of praise for the transmission technology of the current Sram generation in various test environments. However, even the highest quality mechanical shifting groupset with this standard put a lot of pressure on the scales and has not yet been able to satisfy racers in particular. Sram reacted and advertised the Eagle 90 SL with all the advantages of the basic version at a significantly reduced weight. The highlight: the "SL" is actually not new at all. It simply combines the mechanical components of the Sram Eagle 90 with weight-optimised components from the Eagle XX SL transmission assembly. Clever!

Weights and prices of the Sram Eagle 90 SL Transmission at a glance

>> We have summarised even more information on the mechanical Sram Eagle 70 and Eagle 90 Transmission gears here.

Accessories

>> You can find our comparison test between Sram Eagle 90 Transmission and Shimano XT here.

Mechanical but light

The Sram Eagle 90 borrows many technologies from its Funk siblings: direct frame connection without derailleur hanger and protruding parallelogram constructions in favour of durability, large cassettes for the gear range and massive cranks for stability - all of which naturally weighs more. Compared to a classic Shimano XT twelve-speed drivetrain, for example, a Sram Eagle 90 drivetrain weighs a good 270 grams more. Of course, that's a big number on the drivetrain alone and can put off weight-conscious bikers - technical advantages or not. A lightweight alternative is easy to find for some components. After all, the Sram Transmission portfolio works according to the "mix and match" principle. The upgrade from the Sram Eagle 90 crank and chainring to an XX SL model alone saves around 350 grams and thus makes up for the gap to Shimano.

>> How does the brand new Shimano XTR Di2 fare against the Sram XX Eagle Transmission? Find out in our electric gear duel.

The combination with a Sram XX SL cassette saves another 100 grams on the rear wheel. The XX SL chain brings a small weight bonus with around 18 grams less compared to the Sram Eagle 90. If you want to go all out, replace the aluminium cage of the mechanical Transmission drivetrain with a lighter carbon one, which is available separately as a spare part. A small update that saves nine grams. All other mechanical components of the groupset remain the same: The shift lever without handlebar clamp weighs 117 grams, the rear derailleur with tuning cage 382 grams. In total, a full Eagle 90 including the cables weighs 2108 grams according to our laboratory measurements, while the Egale 90 SL assembly weighs 1573 grams and thus saves an impressive 535 grams. This means that the Sram Eagle 90 SL easily undercuts the lightest electronic transmission groupset from Sram, the XX SL with 1712 grams.

>> By the way, all mechanical transmission circuits can also be converted to wireless technology. You can find the information in this article.

Costs and added value

Of course, integrating the Sram XX SL Transmission components into the mechanical shifting group according to the mix-and-match principle is quite expensive. In total, a consistent Eagle 90 SL costs 1890 euros. Compared to the standard components of the Eagle 90 groupset, this is a hefty surcharge of over 1100 euros for a saving of a good half a kilo in weight. The upgrade of the crankset and cassette, in particular, cuts the pounds, but also drains the bank balance. By comparison, a mechanical Shimano XTR groupset is cheaper and even lighter. However, in our test experience, it does not offer comparable shifting precision - especially under load. A Sram Eagle 90 SL upgrade kit is not planned by the manufacturer. If you want to buy the groupset in this configuration, you'll have to buy the individual parts yourself. The Sram Eagle 90 SL Transmission is probably the most functional mechanical groupset currently on the market, but it remains an expensive, collector's configuration.

>> Electronic or mechanical, Shimano or Sram? All prices, weights and information on the currently most relevant groupsets can be found here.

>> In this article we reveal how Sram Transmission drivetrains can be correctly adjusted.

Conclusion

Finally a lightweight, mechanical transmission drivetrain! The Sram Eagle 90 SL combines a function that impressed us in the test with a significantly reduced overall weight. This means that cable-operated shifting is back in fashion on lightweight cross-country and marathon bikes. Unfortunately, the inclusion of the XX SL parts pushes the price up painfully. - Jan Timmermann, BIKE test editor

>> The Sram Eagle Transmission 1987 special model is also particularly stylish. All information under this link.