Cervelo Aspero 5 Stiffness

Picked up an Aspero 5. This bike is super stiff. It was really fun to feel that direct acceleration when putting down power, but the bike can feel a bit harsh over a longer ride. I figured putting some bigger tires (Pathfinder 42s) would soften the bike, but it didn’t seem to reduce the harshness (distributing the road feel) into my body. I’m wondering if someone has gone done the rabbit hole of where this stiffness is originating and what mitigation measures they have done. Is it the carbon bars, the seat post, the carbon saddle, the Reserve Wheels, the stem? FWIW - I have this di2 bike stock currently. https://www.competitivecyclist.com/cervelo-aspero-5-grx-815-di2-gravel-bike

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I have the regular Aspero (only minor differences in the frame design) and don’t find it unduly harsh. What PSI were you running on the old tires and what are you running with the 42’s?

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I don’t have that bike, but know a lot of people that do. I’ve also heard that it is not a comfortable ride. May just be the trade-off of having a stiff road bike like racing gravel bike.

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indeed… big volume tires need less pressure…
(and what is the rim width? I just switched around a lot of stuff… from an old alloy bike with narrow rims (17??) 28 mm tires and inner tubes, to a few different wheels on a systemsix. 65 mm wheels with 17mm rims and 25 mm tires felt less comfortable, but the difference didn’t shock me. But the last ride was on zipp 303 with 23mm internal width, 28mm tubeless tires and that was really comfortable (and fast).
After some discussions, the extra volume due to the 23mm internal width really helps, + supple tires too
(and of course lower pressure)

What size bike? How tall are you? How much seat post is showing? Pic of the bike?

Lowering your tire pressure, fit changes, and putting the Ergon leaf spring seatpost are likely your only options.

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I’ve got the full cane creek eesilk setup on my aspero and it’s great. Easier than getting a whole new bike and you still retain the high BB stiffness for power transfer. Biggest tires you can fit and aluminum wheels also help.

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Suspension / flexy stem & seatpost are my go-to recommendations after double-checking tires & pressures first.

I prefer the Redshift Stem but the eeSilk is also a good option. I prefer the eeSilk suspension post over the Redshift for weight and basic function in a simple package. The Ergon and even Specialized Terra are leading options for rigid posts that flex well if you have a decent amount of post exposed.

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That would be a good suggestion.
If he’s taking a pounding with tires at the right pressure on the right terrain, often a front/rear ride quality variation should be looked at. Like on a car, you generally want the rear about 20% softer than the front. You can ride a pretty stiff bike if the front and rear have the same ride rate, as you’re not getting rocked back and forth as much. If he’s not showing any seatpost, softening the bars isn’t going to make his life much better; it would like even be perceived as worse.

  • True for the flex style seat posts, but the actual linkage suspension posts give great ride comfort regardless of exposed post.

I do agree that generally matching the front and rear for good balance in feel and comfort is key. I started with a Boone and it’s excellent Isospeed frame that is perfect for gravel use. But the bike felt unbalanced with the stock rigid stem. Adding a Redshift stem was the right match to make the bike comfortable and “even” between both ends.

That said, we haven’t heard if the OP has specific issues with one end more than the other, or more of a “both” aspect (my guess). That answer may guide specific placed to add or skip component changes.

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160 lbs. 32 psi. The tires measure out at 44.

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I’m ~155 and run ~25psi on 40mm tires, and 23psi on 42mm tires.

I would recommend taking out some pressure and seeing how that feels. Maybe start at 28psi?

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Those are really low pressures. The problem isn’t suspension on the bike, it’s a fit issue.

Care to expand on that? I wouldn’t rule out fit as a factor without some more info, but blaming fit without any actual rider & bike fit info to that end seems like a stretch at this time.

I think that there can still be vibration related issues here even if the tires & pressures are considered acceptable, and even if fit is perfect.

To be clear, I am not suggesting he run pressure as low as mine…but If his problem is “stiffness” than lower pressure will help. I am assuming he has a good fit, based on his post.

To me, 32psi on a 44 seems like higher than necessary psi…and yes, I know it is realtively clsoe to Silca recommendations, but I also find their recommendations to be on the high side…for me.

Trying a couple of rides at 28psi is a cheap and easy way to see if he can solve his comfort issue.

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Agree with that logic. I too have found the Silca suggestions to be high. I usually use Silca and the SRAM site and then play around from there. I find myself settling a little lower than Silca but it is a good starting point.

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What are you coming from? It’s stiff like a race bike so if you are coming from an endurance bike it’s likely going to take some time to adjust.

Yes - I come from a first gen diverge which is effectively an endurance bike. I’m on the tall end of a 56 with a LOT of seat post showing. My other comparison is a Madone which is ultra, ultra comfy with a more aggressive fit. Originally, my plan was to do an N-1 with the Madone/Diverge and get a set of road wheels for the Aspero. I quickly gave up on that plan as I’m substituting the Diverge for long days in the saddle still.

My fit is identical to what I’m coming from (and recently had fit) so I’m not concerned here.

When I think about the harshness, I really feel it on the ‘off-road’ sectors and if I hit any potholes. Perhaps the answer may lie in the AB09 flared handlebars which are different than the OG Aspero.

I recently had a natural experiment with my carbon Next SL large 35 diameter bar on the rigid fat bike. Put my old Bontrager bars on temporarily and when I came back to the Next SL it was shocking how much harsher they were even with 4 inches of rubber underneath me. Just zero flex. I think the same thing may be going on with the Cervelo carbon flared bars. They both appear to be a superconductor of any square edged hits.

Do I need to suck it up and understand that this is the tradeoff for a pure-bred gravel race bike? I’ve heard the Cervelo S5 is similar in nature on the road. Or can you have a stiff, power-efficient frame that doesn’t beat you up over time?

  • Not necessarily, and that’s why several of us mentioned stems and seat posts with more flex or even suspension included.

Specifically if you expect that bar you chose is overly stiff, a suspension stem may be the perfect remedy. Similar for the seat post. Great to have the extension you seem to have, but not all rigid posts are the same. The Ergon and Specialized mentioned above were designed specifically for more flex to improve comfort.

I think you owe it to yourself to check those out if you like the rest of your setup other than the impact and vibration issues.

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I would again recommend starting with tire pressure and see what gains you can achieve there. It is free and easy!

HB stiffness can definitely play a role in comfort. I switched to the ENVE AR Road, which while having a flat, aero top, is which thinner in width than most aero bars. As a result, it is pretty damn comfortable off road. IIRC, a few months ago there was a Geek Warning pod where they talked about a growing trend of less stiff HB setups and the added comfort they can bring. COuld be worth checking out.

I would also strongly recommend the use of a suspension seatpost…I have noted many times that I have used one for literally decades. Had one on my old hardtail, used then on my CX bikes and now use them for gravel. I went a a few months with a rigid post after my 20 year old USE suspension post’s bushings gave out and I hated it. I got the Ergon post @mcneese.chad mentioned and I love it…not quite as active as a telescoping or parallelogram style post, but very comfortable and with a minimum of weight penalty. I’ll definitely be using it for Unbound this year!

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My comparison was a 2015 Trek Domane and a Specialized Tarmac SL7. Tires and pressure on the Tarmac make a big difference