# Thread: Giant 27.5 technology query

1. ## Giant 27.5 technology query

As most would be aware, Giant offered a webpage to explain their findings regarding "27.5 technology" i.e.:

Showcase: Anthem Advanced 27.5 - Giant Bicycles | United States

There's a at least 3 things I have issues with on this page, but I only want to raise 2 for discussion.

(1.)

Under "Better Control" it states:

"A larger contact patch results in better traction, which leads to improved acceleration, deceleration and cornering."

Surely this is incorrect, accelerations would favour the smaller contact patch. Even the comment is self-contradictory if you read the previous section where it clearly references the 26" as the fastest accelerating wheel and in fact uses it as a basis for the others.

(2.)

Most would be familiar with this graphic:

...which came from the following very interesting page

650b/27.5? Mountain Bike Round Up | Mountain Bike Review

...the key point being that the circumference of the 650b is NOT halfway, but rather biased towards the 26" (39% as opposed to 50% (middle)).

However ...Giant show:

...if so, then how can the contact patch of the 650B be 8cm (where the 26" and 29er are 6cm and 9cm respectively)?? I.e. closer to the 29er?? One would expect the contact patch to be closer to the 26", by calculation; 0.39*(9-6)cm +6cm = 7.17cm.

Thoughts??

2. I think what they're getting at with "A larger contact patch results in better traction, which leads to improved acceleration, deceleration and cornering." is if you can't get traction then you can't accelerate as quickly. If you're getting wheelspin, regardless of how quickly the wheel itself can accelerate, you're not going to get up to speed as quickly.

Regarding point #2, I think you're on to something there...

3. If you don't have traction, you don't have acceleration, period.

As to 2: depends on tire size and tread height, now doesn't it?

4. 27.5 with 5 PSI creates an 8 cm contact patch and when combined with a Schwable Racing Ralph 2.25 reinflated to 60 PSI provides a diameter right in between 26 & 29. It's all in the fine print.

5. ## Re: Giant 27.5 technology query

Ignore the traction thing..I believe it is saying that it is improved acceleration in comparison to a 29er. The tires you are running are going to have as much if not more to do with traction than the contact patch.

--
Stephen

6. Originally Posted by rideit
As to 2: depends on tire size and tread height, now doesn't it?
The point of that article was to use as similar tire as possible to make the comparison legit, otherwise what would be the point.

7. there's fine print? where

Originally Posted by YogiKudo
27.5 with 5 PSI creates an 8 cm contact patch and when combined with a Schwable Racing Ralph 2.25 reinflated to 60 PSI provides a diameter right in between 26 & 29. It's all in the fine print.

8. Originally Posted by lucifuge
The point of that article was to use as similar tire as possible to make the comparison legit, otherwise what would be the point.
That may very well be, but, in reality, were/are the tires (often) used in comparisons like this similar or equivalent?

9. ## Re: Giant 27.5 technology query

Originally Posted by YogiKudo
27.5 with 5 PSI creates an 8 cm contact patch and when combined with a Schwable Racing Ralph 2.25 reinflated to 60 PSI provides a diameter right in between 26 & 29. It's all in the fine print.
Good gawd 60 psi?

--
Stephen

10. If you want the most objective/scientific comparison to show the relative difference between the wheels you hold as much of the tire characteristics static/consistent in order to arrive at viable conclusion. Apples with apples gets answers, apples with oranges don't. To be deliberately facetious, you might be able to add a tire and inflate it so its circumference is greater than a 29er, apart from looking ridiculous, whats the point?

I'm simply trying to draw a comparison between that finding and the one Giant made which on the surface seems counter intuitive.

Originally Posted by rideit
That may very well be, but, in reality, were/are the tires (often) used in comparisons like this similar or equivalent?

11. In Giant's case, when you put most of your eggs in one basket you'd better have a damn good reason why (or create the illusion that you do). Hence a long explanation of the 650b benefits/drawbacks.

Mildly amusing. I can't remember the last time I was out riding and wished I had 9.8% better rollover capability or that I could accelerate 1.5% faster.

12. Originally Posted by Berkley
Mildly amusing. I can't remember the last time I was out riding and wished I had 9.8% better rollover capability or that I could accelerate 1.5% faster.
Not only are those percentages small, how much of the ride involves such considerations lol

13. Giant is full of sh!t with their recent marketing campaign. Everyone of their statements is made up and has no basis in real life. Yep, I said it. And...I work at a shop that sells Giant. Go figure. I've taken the time to measure the roll out of three different Giant Trances, All with Nobby Nics, all the same PSI. The 27.5 was MUCH closer to the 26 than it was to the 29. Contact patch difference between the 26 and 27.5 was so negligible that you could hardly tell the difference.

27.5 exists for this reason IMO: 26 has been around for a long time. 29 came on board, went big and brought in a lot of new sales for companies. Now, 26 is dying off in many markets. Yet, you have many customers who feel stranded. They like their old 26 and don't feel comfortable on 29ers. So, what do you do? You go big with a new wheel size that is a bit bigger but not so big as to turn off the people who don't like the bigger 29ers. I swear, if you could ride a 26 and 27.5 back to back, blindfolded, you wouldn't be able to tell me which one you were on.

14. so im not going completely nuts with my findings then lol

Originally Posted by Silentfoe
Giant is full of sh!t with their recent marketing campaign. Everyone of their statements is made up and has no basis in real life. Yep, I said it. And...I work at a shop that sells Giant. Go figure. I've taken the time to measure the roll out of three different Giant Trances, All with Nobby Nics, all the same PSI. The 27.5 was MUCH closer to the 26 than it was to the 29. Contact patch difference between the 26 and 27.5 was so negligible that you could hardly tell the difference.

27.5 exists for this reason IMO: 26 has been around for a long time. 29 came on board, went big and brought in a lot of new sales for companies. Now, 26 is dying off in many markets. Yet, you have many customers who feel stranded. They like their old 26 and don't feel comfortable on 29ers. So, what do you do? You go big with a new wheel size that is a bit bigger but not so big as to turn off the people who don't like the bigger 29ers. I swear, if you could ride a 26 and 27.5 back to back, blindfolded, you wouldn't be able to tell me which one you were on.

15. Giant's ad campaign is a little heavy. Giant is arguing with this ad campaign that their bikes are faster because they are "just the right size"...and this goes against what they said in the ad video for the Trance 29'er.

At the moment, I prefer a 29'er because I like the smoother ride. I will try the new wheel size out of curiosity. I also find that once the wheels feel faster the faster I go, and I don't really notice any acceleration issues. Momentum counts. Maybe it depends on the course.

Over the next year and onward, watch the reviews and comparisons, race results and sales. I am fine to have a new wheel size in the mix, but the arguements of it's superiority are questionable. Besides, even if one wheel size was "fastest, or best" in an average scenario, or a specific scenario, the other wheel sizes will still have genuinely desirable benefits that justify their existence.

16. The thing is that many of us don't want anything bigger than 27.5 for this kind of bike, so all of that vitriol is meaningless.

17. Originally Posted by rideit
The thing is that many of us don't want anything bigger than 27.5 for this kind of bike, so all of that vitriol is meaningless.
Many don't, but others do. Giant is saying everybody should be satisfied with 27.5 and nobody needs or should want anything bigger. I am not criticizing the wheel size, just the marketing that insists that 27.5 is better than 29'er for everybody. I don't think they can make that claim.

18. However, it's not worth fretting about, or over analyzing. Ten years ago the PM at Giant said hey would never, ever produce 29-ers, either.
Ultimately the market dictates Giant's production decisions.

19. Originally Posted by rideit
However, it's not worth fretting about, or over analyzing. Ten years ago the PM at Giant said hey would never, ever produce 29-ers, either.
Ultimately the market dictates Giant's production decisions.
Fair enough. My issue though, is that Giant's forceful 27.5 marketing and the hype in general could cause the illusion of 27.5 becoming the most popular in the very least in the short term, because some folks get sucked in, or others just want to try it out. If decisions like stopping 29'er production are made too soon, then I would be more than disappointed with Giant. Not the end of the world, I can find a good FS 29'er later, but it's annoying that some companies are trying to push 27.5 so hard as to eliminate the other wheel sizes. Anyways, like I said, we'll wait and see what the results are in races, sales, reviews etc.

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