There seem to be some good answers on MTBR from a couple years ago....
https://forums.mtbr.com/trek/knock-block-yay-nay-1074273.html

I've done a fair bit of technical racing with the knock block that came with my Fuel Ex including many tight switchbacks and didn't find it a problem in the slightest. I did speak with one woman riding a much smaller frame who wasn't a big fan - I'm not sure if frame size has anything to do with it or just that it was personal preference; I just can't picture turning the bars that tight at speed.

Any handling deficiencies I encountered had nothing to do with knock block or the bike in general (except for the tires it came with). While Trek wasn't my first choice, I couldn't resist the great deal I got on this media bike and boy am I ever glad I did - phenomenal ride.

---

Kiwami NA Racing Team

my 2 cents...

I currently have my cockpit at a [slightly] less than ideal configuration so that my brake levers don't smack the top tube of my frame when i crash. Having a knock block would protect my top tube and allow me to drop my handlebars a little more and angle my brake levers down to where i really wanted them.

However, it would also prevent me from fitting the bike the in trunk of my small 2dr e46 m3. My handlebars need to be turned further than the knockblock would allow in order to get my bike in the trunk. So for me, even though the knock block would have some benefits, it's a deal breaker. I don't want to have to keep my MTB on the roof at all times.

Personally, i wouldn't be worried about the steering angle in tight switchbacks.

I have a Supercaliber that comes with Knock Block.

The limitation I have is around the ability to run my handlebars low enough with Knock Block. The stems available with knock block are 13 and 6 degree stems. That doesn’t get my bars low enough for my preferred fit. You can also run the 1cm knock block spacer and pair it with a non Bontrager stem, but running the 1cm spacer with a 25 degree stem is a near wash.

My remedy for this can be seen in the attached pics. I am not utilizing knock block. I fabbed a replacement knock block chip, am using a low top cap, and a zipp 25 degree stem.

The Supercaliber comes with a frame saver pad on the downtube to prevent and potential fork interaction with the frame from causing damage. I am running the SID SL ultimate fork and there is no overlap between the fork and downtube. I moved and cut the pad from the downtube and placed it on either side of the top tube. This protects the top tube from coming in direct contact with the AXS shifter and dropper controllers. So far so good.

---

____________________________________________________

Wife had the smallest size Fuel EX and knock block was an issue on switchbacks. She always complained about it, but I never believed her. Then I tried riding her bike and corners I had no problem with on my bike were nearly impossible on hers.

Im on a M/L super caliber and not an issue... that i know of...
daved

---

http://www.theundergroundcoach.com

This is 100% my experience (except talking to a woman rider with a smaller frame) on a large 2018 Fuel EX with a couple of different stem lengths and bar widths.

I messed up my previous fat bike frame (No Knock Block) on what I thought was a fairly innocuous snow crash, so I'm personally a fan.

2018 Fuel Ex size large here. No issues. That said, I've heard different takes on it from different models and sizes so YMMV.

Possibly my all-time favorite car. Sweet, sweet inline 6.

I just rode Supercaliber with knock block for the Maah Daah Hey 150. Zero issues and there are some crazy sharp switches. Its simply a glorious bike with AXS. And I swear the wireless dropper has to be the best piece of cycling tech on earth ;) I used it like...100 times or more during that race.

Only drawback I see is hauling. Turning the bars further than knock blick allows is ideal when hauling in a pickup bed on the bike's side.....

---

24 Hour World TT Champs-American record holder
Fat Bike Worlds - Race Director
Insta: chris.s.apex