Seatposts
The second most likely part requiring a change during your Bike Fit is the seatpost, but it’s not nearly as often as with the stem. The reason is that the seatpost has a lot of adjustment which is usually sufficient for most people to retain their existing component.
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Most bikes are traditionally supplied with an ‘offset’ seatpost with 10-25mm of rearward layback. This has been the case because the layback allows a ‘proper’ saddle position on a road bike (hip-marker broadly in line with the seat tube axis) without resorting to excessively long chainstays and / or unusual seat tube angles. The layback can also add an element of micro suspension.
But in these days of disc brakes and fatter tyres, some more enlightened manufacturers are taking advantage of these new norms and fitting inline seatposts. The best example of this, and the best explanation for why, can be found by Gerard Vroomen (he of Cervelo) with his brand of OPEN gravel and road bikes. See the OPEN website description of the U.P. gravel bike to learn more.
PRO PLT Seatpost - £59.99
Again, the primary offering is the PRO PLT Seatpost for the same reasons we like the stem. It is also 3D forged, this time from 7050 aluminium, and it’s got a textured anodized black finish which is long lasting and helps grip the post in the frame.
The head has unlimited angular adjustment and is very secure in use, unlike some other seatposts with similar 1-Bolt Clamp System. This has a sensible 13Nm torque requirement which is high enough to sound secure, but not so high that it makes you fear for the wellbeing of the threads.
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This seatpost is available with 0mm and 20mm laybacks in the most common 27.2mm and 31.6mm diameters. Its length is 400mm and can be easily cut down during your Bike Fit as required.
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Like the PLT stem, it’s a discrete and attractive component which will suit most bikes.
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Of the three PRO seatposts I stock, I’d recommend the PLT unless there is some sizing reason that restricts you to the others, simply because of its higher Perceived-Quality. It’s also slightly stronger and lighter by dint of its better materials and manufacturing process, but let’s face it, looks usually win-out for most people.
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Mass: 27.2mm inline: 259g, 27.2mm 20mm layback: 285g
31.6mm inline 257g, 31.6mm 20mm layback: 296g
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PRO LT Seatpost - £49.99
The design of the LT is virtually the same as the PLT. It’s just a little less refined and uses slightly cheaper materials. For me it’s not worth the £10 saving over the PLT but the reason I stock it is because it comes in a 30.9mm diameter, which the PLT does not, and it does look better on some bikes. Like its more expensive sibling it is also 400mm in length and available with a 0mm or 20mm layback.
It has a lower 8Nm torque requirement than the PLT (which it shares with the Tharsis 9.8 below) due to it heavier bolt and clamp mechanism.
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Mass: 27.2mm inline: 300g, 27.2mm layback: 315g
30.9mm inline: 284g, 30.9mm 20mm layback: 304g
31.6mm inline: tbc, 31.6mm 20mm layback: tbc
PRO Tharsis 9.8 - £59.99
Tharsis is PRO’s MTB range and the Tharsis 9.8 seatpost is nominally a ‘downhill’ seatpost made from the same forged 7050 aluminium as the PLT.
We’d be really pushing the Bike Fit to its limits if we need a 10mm layback instead of 0mm or 20mm but it may be suitable for some people, so hold it in limited stock for this reason.
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Its slightly shorter at 350mm which allows it to come in at the ‘same’ mass as the PLT and we stock it in the 31.6mm diameter.
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It has a lower 8Nm torque requirement than the PLT (which it shares with the LT above) due to it heavier bolt and clamp mechanism.
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Mass: 31.6mm 10mm layback: 248g