{"id":68788,"date":"2024-09-05T15:00:00","date_gmt":"2024-09-05T13:00:00","guid":{"rendered":"http:\/\/137d4b2c-b5c9-4405-a331-00b2d5ee44a2"},"modified":"2024-09-05T15:25:28","modified_gmt":"2024-09-05T13:25:28","slug":"tech-qa-how-to-get-the-right-dropper-length-sram-udh-conversions-and-the-history-of-pedal-threads","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/cyclingplus\/rss_feed\/tech-qa-how-to-get-the-right-dropper-length-sram-udh-conversions-and-the-history-of-pedal-threads\/","title":{"rendered":"Tech Q&A | How to get the right dropper length, SRAM UDH conversions and the history of pedal threads\u00a0"},"content":{"rendered":"

Our experts answer your questions <\/p>

By Oscar Huckle\n <\/p>

Published: Thursday, 05 September 2024 at 13:00 PM<\/p>

\n\n

Welcome to the August edition of our Tech Q&A, where we aim to answer your questions, tapping into our unparalleled access to the greatest minds in cycling \u2013 both on the BikeRadar staff and externally.\u00a0<\/p>

Senior technical editors Tom Marvin and Warren Rossiter sat down with technical writers Luke Marshall and Oscar Huckle to answer your questions.\u00a0<\/p>

For this edition, we received questions on getting the right dropper length, whether non-SRAM UDH equipped frames can be converted and replacing a fork with an aftermarket option.\u00a0<\/p>

As ever, if you have a question you can\u2019t find the answer to, email us at podcast@bikeradar.com<\/a>. We\u2019ll select the most interesting questions every month and bring you an expert response.\u00a0<\/p>

Getting the right dropper length\u00a0<\/h2>
Simon asks\u2026\u00a0<\/h3>
Simon wants to get the most drop for his buck. – Mick Kirkman \/ Our Media<\/figcaption><\/figure>
How can I determine the most drop from a dropper post I can fit in my frame? There seems to be a wide range of drop lengths available and I want to get the most possible out of my 2021 Giant Trance.<\/p>
BikeRadar\u2019s answer\u2026\u00a0<\/h3>
$\"Merida$
You might as well maximise your drop potential \u2013 here’s an example where there’s a lot of exposed seatpost. – Andy Lloyd \/ Our Media<\/figcaption><\/figure>
Gravity-focused maestro Luke Marshall says there are short and long answers to this question. The short answer is you can take a look at a few dropper-post calculators online, such as those offered by OneUp Components<\/a> and PNW<\/a>.\u00a0<\/p>
But you\u2019re going to need a few measurements anyway, so we\u2019ll take you through the long answer.\u00a0\u00a0<\/p>
We assume you\u2019re going to keep your saddle, so we don\u2019t need to worry about determining the saddle stack height (the distance between the bottom of the dropper\u2019s seat collar and the post\u2019s saddle rails).\u00a0<\/p>
But we need to figure out the ride height \u2013 how far the rails of the saddles are above the seat tube clamp. You can get this figure by using a tape measure.\u00a0<\/p>
When choosing a dropper post<\/a>, you need to be careful that the post\u2019s extended length isn\u2019t longer than the ride height. Otherwise, the saddle height\u2019s going to be too high and your feet won\u2019t be able to reach the pedals properly.\u00a0<\/p>
You also need to determine the insertion depth. Depending on the model of Giant Trance you have, the 2021 Trance (not the Trance X) has a pivot for the rocker that goes through the seat tube, which is a limiting factor on insertion depth. Conversely, this isn\u2019t an issue on the Trance X.\u00a0<\/p>
$\"Wolf$
Most levers will remove easily from the bar. – Oscar Huckle \/ Our Media<\/figcaption><\/figure>
Remove the seatpost and measure the insertion depth. The easiest way to do this is to remove the dropper post lever from the bar, but leave the cable intact.\u00a0<\/p>
Undo the seatpost clamp and pull the dropper seatpost up so you\u2019re not stretching anything.\u00a0<\/p>
Once the seatpost is out of the frame, grab a tape measure and slide it into the seat tube and extend it until it hits its first obstruction. That will probably be the pivot on this Trance, but it might be a bottle cage bolt.\u00a0<\/p>
Once you\u2019ve got those two figures, you can then do a calculation to work out what post you can use.\u00a0<\/p>
You\u2019re trying to find a post that has a similar height to your ride height, but a bit less. If it\u2019s more, the saddle will be too high.\u00a0<\/p>
Then, see how much insertion depth they have. If the insertion depth of the frame is short, you\u2019re going to limit the amount of drop you can run.\u00a0<\/p>
If your insertion depth is greater than the depth of the seatpost, you\u2019ll have no trouble.\u00a0<\/p>
If the insertion depth is shorter, the seatpost is going to stand proud of the top of the seatpost a little bit.\u00a0<\/p>
Subtract the insertion depth of the frame from the maximum insertion depth of the seatpost. This will tell you how proud a new post will stand.<\/p>
Add that to the dropper length and as long as those two measurements are shorter than your measured ride height, you\u2019re good to go.\u00a0<\/p>
The lower the insertion depth, the lower-travel dropper post you can run. You\u2019ll notice on more modern frames that brands have sorted this issue to enable you to run longer-travel posts.\u00a0\u00a0<\/p>
Using an aftermarket fork\u00a0<\/h2>
Joey Colaizzi asks\u2026\u00a0<\/h3>
$\"Oscar$
Tread carefully if you’re replacing a fork with an aftermarket option. – Scott Windsor \/ Our Media<\/figcaption><\/figure>
Would it be a mistake to replace the stock fork that has a 45mm offset \/ rake and 57mm trail on my 2018 54cm Trek Emonda (H2 geometry) with a fork that has a 40mm offset \/ rake?\u00a0<\/p>
I had to replace the fork in a crash, and when the shop installed the new fork, they cut the steerer tube down to minimum length. That means I\u2019ve now got to slam the stem.\u00a0<\/p>
I need about 20-30mm more stack and, petty as it may be, I don\u2019t love the aesthetics of a stem with 12 degrees of rise.\u00a0<\/p>
The 54cm Emonda frame is the largest size with the stock 45mm-offset fork, so it\u2019s hard to find a replacement fork with a long enough steerer.\u00a0<\/p>
If I could search for one from a larger frame, I\u2019d greatly widen the pool of long steerer tubes, but it would have a 40mm offset \u2013 is that okay?\u00a0<\/p>
I\u2019m an avid recreational rider, not a racer.\u00a0<\/p>
BikeRadar\u2019s answer\u2026\u00a0<\/h3>
$\"Pack$
The handling will likely be more akin to an endurance bike. – Russell Burton \/ Our Media<\/figcaption><\/figure>
Warren Rossiter reckons there\u2019s no need to worry about replacing the fork with a 40mm-offset in this instance.\u00a0<\/p>
Doing a bit of digging, the 2018 54cm Emonda has a 73-degree head tube angle and a standard 45mm offset. That gives you a 57mm trail measurement when running a 25mm tyre.\u00a0<\/p>
By changing to a fork with a 40mm offset, you\u2019ll have a 62mm trail, which is more akin to an endurance bike<\/a> such as the Trek Domane.\u00a0<\/p>
That move into endurance bike geometry isn\u2019t necessarily a bad thing, seeing as you describe yourself as a recreational rider. You should expect the bike to feel more stable and less twitchy.\u00a0<\/p>
$\"Specialized$
A riser bar could be the way to go. – Ashley Quinlan \/ Our Media<\/figcaption><\/figure>
Onto the slammed-stem dilemma. Warren reckons the best option is opting for a handlebar with more rise \u2013 but you\u2019ll struggle to find one with as much as 20mm. Some handlebars Warren suggests include:\u00a0<\/p>
Specialized Hover Bar, which will give you 15mm of rise\u00a0<\/li>
Vision Metron 4D \u2013 although the brand doesn\u2019t quote a rise figure, Warren reckons it\u2019s around 10mm and can vouch for its comfort and quality\u00a0<\/li>
Profile Design DRV \/ GMR with 9mm rise and a bit of flare<\/li>
One of Ritchey\u2019s Ergomax options with 10mm rise<\/li>
Genetic Driser 4 with 20mm rise and 40 degrees of flare<\/li><\/ul>
Oscar also suggests if you want to stick with the original fork, you could try to source one via a second-hand marketplace, such as eBay. You could also contact Trek Warranty. It\u2019s not unheard of for warranty departments to have spare forks and you may have some luck.\u00a0<\/p>
Pedal threads\u00a0<\/h2>
Theo Mulder asks\u2026\u00a0<\/h3>
$\"HT$
Pedal threads are one of very few components where the standard hasn’t changed. – Oscar Huckle \/ Our Media<\/figcaption><\/figure>
Why do pedal threads have a right-hand thread on the right and left-hand thread on the left?<\/p>
Bearings that fail with increasing friction will then tend to unscrew the pedal, which results in the sudden departure of the pedal from the crank. This has happened to me, but luckily when not really pedaling hard.<\/p>
BikeRadar\u2019s answer\u2026\u00a0<\/h3>
$\"Unior$
If it ain’t broke, don’t fix it. – Scott Windsor \/ Our Media<\/figcaption><\/figure>
Oscar explains the Wright Brothers, aviation pioneers credited with inventing and flying the world’s first successful aeroplane, claimed this invention in 1900.<\/p>
Before their days in aviation though, they built bicycles. Originally, both pedals had standard right-hand threads and the left pedal would keep loosening.\u00a0\u00a0<\/p>
As such, they decided to engineer a reverse-thread for the left pedal to combat this problem \u2013 and it\u2019s a design and standard that\u2019s stuck with bicycles ever since.\u00a0<\/p>
When you\u2019re pedalling, the pedals effectively tighten. It\u2019s worth maintaining your pedals and looking after your bearings to prevent this issue from happening.\u00a0<\/p>
SRAM UDH conversion\u00a0<\/h2>
Bryn asks\u2026\u00a0<\/h3>
$\"2024$
A wonderful machine, but sadly not SRAM UDH compatible. – Warren Rossiter \/ Our Media<\/figcaption><\/figure>
I recently bought a Time ADHX 45, which comes with a SRAM 1×12 XPLR groupset. The frame doesn\u2019t have a SRAM UDH dropout.\u00a0<\/p>
Is there anything happening in the market that would allow non-UDH bikes to be essentially retro-fitted to allow the use of the new SRAM Red XPLR AXS groupset (that uses a direct-mount rear derailleur), which requires UDH.\u00a0<\/p>
Otherwise, cyclists in my position would only have the option of an entirely new bike purchase.\u00a0<\/p>
BikeRadar\u2019s answer\u2026\u00a0<\/h3>
$\"You'll$
You’ll need a UDH-compatible frameset to run the new Red XPLR or a Transmission drivetrain. – Warren Rossiter \/ Out Media<\/figcaption><\/figure>
Oscar explains there isn\u2019t currently a product on the market that can convert a dropout to SRAM UDH<\/a>.\u00a0<\/p>
The UDH dropout is specific and enables SRAM to optimise the shifting performance, to the point where it has done away with the limit screws on its Transmission and Red XPLR AXS rear derailleurs.\u00a0<\/p>
The only example that currently comes to mind is the Norco Optic Gen 2, which launched initially with its own derailleur hanger, with the brand then retrofitting a SRAM UDH hanger later in its product cycle.\u00a0<\/p>
If you own a steel or titanium bike and want to run a direct-mount rear derailleur<\/a>, you could look into getting your dropout replaced, but for all other materials, the answer is currently no.\u00a0<\/p>
It\u2019s important to note we\u2019re still in the early days of SRAM UDH\u2019s lifespan and Warren says he wouldn\u2019t be surprised if something comes along as a solution to this problem.<\/p>