Various stem weights (all 120mm):
ITM millenium: 147g
ITM The stem (magnesium): 95g
3TTT Zepp XL: 167g
Syntace F99 260: 100g
The Zipp 145 carbon stem is constructed of high modulus carbon fibre, with a lightweight 7075 aluminium chrome-look face plate. Zipp have used 6al/4v titanium bolts and carbon top cap. It is reversible 82° or 98° which means it has a slight rise when flat and when flipped it isn’t ludicrously high (it’s similar to ITM millenium in geometry). Obviously it can be used with a 1.125″ or 1″ steerer and there’s a spacer shim provided, the clamp has a two sided bolts and they work against each other to prevent any uneven twisting of then stem when you tighten it.
The Zipp stem comes in a very nice presentation box and the titanium bolts are already prepared with ti-prep to prevent them from seizing into the aluminium threaded inserts set into the carbon body of the stem. We assembled it using a torque wrench to the recommended settings and took great care to get the gap between the clamp and stem equal top and bottom. The four fixing bolts are precision made from 6al/4v titanium as are the ones at the steerer clamp, which is a good idea as the sweat and rain won’t rust them up.
Well it was a dream to fit but how did it ride? The previous carbon stem approach to manufacturing has been a tube bonded to two aluminium clamps. This is partly because it was hard to mould carbon and partly because the aluminium made the clamps more serviceable. The increase in performance was minimal but the increase in wow-factor was considerable. Zipp have used their high modulus carbon fibre and moulded in the appropriate aluminium inserts for the threads, so they have essentially a complete stem from carbon with no glue and I think I’m not alone in thinking I want my stem to be free from glue and made from one piece.
Looks-wise it’s a bit of a love/hate thing. The chrome finish front cap will add a bit of ‘bling’ to your ride and the oversized stem initially looks huge from sitting in the saddle, but as bars and frame tubes get bigger, so should stems and there’s certainly something to say about how solid the 145 stem feels… The clamp area is exceptionally well finished and fitted to the steerer pefectly. The carbon Zipp top cap and stainless steel bolt are a neat touch and will add final finish to the complete carbon look. The finish is superb too, but at this price it wants to be.
As technology improves more and more carbon components will reach your bike but few will add as much difference as a solidly built carbon stem like this. Zipp have successfully made a one-piece unit which makes you feel that little bit more secure over previous bonded units, not that there was anything wrong with them but the price rarely justified the small increase in performance (weight, rigidity etc).
However it’s not just a pretty face as it certainly seemed to reduce a little of the road buzz when we swapped the bars on the Trek Pilot 5.2 earlier this month. Not only do Zipps bars feel and work better than the Bontrager Flat Tops, the 145 stem took some aggression out of the forks. Performance and quality are second to none, but value is low down the list – it’s going to be the sort of thing that you just have to have.
We’ve tried the standard size and the oversize and find them comparable weight-wise with the oversize being noticeably more burly in the sprint. Much as it’s a pain to have to fit lights and computers to fatter bars they do add something ‘stiffness’-wise to the sprinting platform…
… and next up we’ll be writing about the equally pricey matching carbon handlebars, but can they match the performance of the 145?
Verdict: It’s light, it stays put and you can’t bend it. But how much?