New-Old-Stock Shimano Dura-Ace UniGlide (6 and Possible 7-Speed) Freehub (36 Hole / 126mm Spacing)… Some Shopwear Thank you for your interest in this item and please visit our store for other offerings. The 6/7 Speed Discussion I have been fortunate enough to acquire a few Shimano Dura-Ace 7-speed UniGlide freehubs that are very similar to this 6-speed model. This price difference caught the attention of a few customers and one in particular was interested in better understanding the differences between this 6-speed unit and the more expensive 7-speed unit. I have to admit, I became curious as well, and proceeded to inspect them side-by-side. To my surprise, the first noteworthy feature is the actual hub bodies are identical (meaning the splined and threaded component that holds the cassette has the same dimensions for both the 6 and 7-speed freehub). This then begged the question about fit, as a 7-speed UniGlide cassette has a slightly wider footprint relative to a 6-speed UniGlide cassette. So I proceeded to thread a 6-speed cassette and a 7-speed cassette to assess the difference. As it turns out the 6-speed threaded lockring sprocket will cinch down deeper onto the threaded section of the hub body before it locks the splined sprockets and spacers into place. Not surprisingly, the 7-speed lockring sprocket cinches down on the splined sprockets and spacers much sooner, but it is still seated over a number of the threads for a secure fit. This leaves us with only one problem to address with the 6-speed freehub and the 7-speed cassette, and it is the drive-side spacing. Said another way, both the 6-speed freehub and 7-speed freehub are spec’d to the same 126 mm locknut-to-locknut dimension, but the 7-speed freehub will have more drive side spacing relative to the 6-speed freehub. Likewise, the 6-speed freehub will have more non drive side spacing relative to the 7-speed freehub. This all makes perfect sense, because the total spacing for both freehubs must equal 126 mm. Although, such spacers may be re-positioned to effectively turn a 6-speed freehub into a 7-speed freehub, or a 7-speed freehub into a 6-speed freehub. Of course, there is not much incentive to do the latter, given the high cost of the factory 7-speed freehubs I have in stock, but there is some incentive to do the former. In other words, a re-positioning of the spacers on one of these 6-speed freehubs will turn it into a 7-speed freehub (and will do so at a lower cost). If you recall, I mentioned there was one particular customer that was interested in this 6-speed vs. 7-speed freehub discussion and that customer ended up successfully turning one of these 6-speed freehubs into a 7-speed freehub. I have copied his feedback regarding the experience with the hope that it helps someone else.. Just wanted to update you, as I said I would, about the compatibility of a Dura Ace 7400 series 6-speed UniGlide freehub with a 7-speed drivetrain and UniGlide cassette. The freehub is completely compatible with a 7 speed drivetrain with the following modifications. As we both surmised, all one has to do is move the one silver washer from the non-drive side to the driver side. That is the only difference between the 6 and 7 speed versions of this freehub. The index shifting works great. So you can pass that information on with confidence, if you wish. This offering is for a new-old-stock Shimano Dura-Ace 6-speed freehub (model FH-7400). Please note the 7-speed conversion discussion above. Detailed specifications include the following.. Locknut dimensions: 126 mm. Cluster compatibility: 6-speed Dura-Ace specific UniGlide cassette. Axle type: hollow type with matching quick release skewer. Other specifications: For those that want to know the specific hub body length or said another way… The length of the splines on the hub body, we measure them to be 29 mm (and this includes the 6 mm external threaded section for a 6-speed Dura-Ace specific UniGlide cassette). This same reference material also indicates the cup-n-cone bearing design is enhanced to include some sealing properties that should help reduce internal wear. Now I will be the first to admit these sealing properties are not on par with more current cartridge bearing designs, but I believe Shimano’s claim still holds some merit. As for condition, this is a new and unused freehub with no evidence of lacing on any of the spoke holes. Shimano designed/manufactured their Dura-Ace Uniglide cassette/freehub systems to different specifications relative to their other UniGlide systems. The splined cogs and spacers (and the related splined section of a UniGlide hub body) are similar for all Shimano UniGlide models, but the smallest UniGlide sprocket that threads onto the end of a UniGlide hub body is spec’d to different standards. More specifically, Shimano made their Dura-Ace threaded sprockets (and the threaded section of their Dura-Ace hub bodies that accomodate them) with a smaller diameter relative to their other UniGlide systems. We measure Shimano threaded UniGlide cogs (with the exception of Dura-Ace models) to be about 33.5 mm in diameter and they will thread fine on just about any non Dura-Ace UniGlide freehub. However, Shimano’s Dura-Ace threaded UniGlide cogs are spec’d to a smaller standard… With only a 31.0 mm diameter… And are only compatible with Dura-Ace UniGlide freehubs. Please keep in mind this is only an issue with threaded UniGlide sprockets, as all splined UniGlide sprockets and spacers are interchangable on just about any UniGlide freehub… You may visit our store by clicking on this “Store Home Page”. Link and please note the product categories on the left side of our “Store Home Page”. We have also moved our “Terms and Conditions”. You may navigate to this page by clicking on the link on the left side of our “Store Home Page”. Unfortunately, this service is more expensive, especially for smaller/lighter packages, relative to the First Class International service. The item “NOS Shimano Dura-Ace UniGlide (6 and Possible 7-Speed) Freehub (36 Hole/126mm)” is in sale since Friday, June 9, 2017. This item is in the category “Sporting Goods\Cycling\Bicycle Components & Parts\Hubs”. The seller is “bicyclists_retreat” and is located in Argonia, Kansas. This item can be shipped worldwide.
- Model: Dura-Ace
- Country/Region of Manufacture: Japan
- Custom Bundle: No
- Number of Spoke Holes: 36 Hole
- Color: Silver
- Part Type: Freehub
- Compatible Bike Type: Road Bike
- MPN: Does Not Apply
- Modified Item: No
- Type: Rear
- Non-Domestic Product: No
- Brand: Shimano